Zizhi Tongjian (资治通鉴): Sima Guang’s Comprehensive Mirror for Rulers

The Zizhi Tongjian (资治通鉴), the Comprehensive Mirror to Aid in Government, is one of the greatest works of history ever written. Compiled by Sima Guang over nineteen years during the Northern Song dynasty, it covers 1,362 years of Chinese history from 403 BCE to 959 CE in a single chronological narrative. This pillar page explores its origins, its method, its political context, and its lasting influence on how we understand governance, institutions, and the relationship between power and consequence.

For readers interested in the broader tradition of Chinese historical writing, the Shiji (Records of the Grand Historian) by Sima Qian, covered in detail at our Shiji pillar page, is the other foundational work of Chinese historiography, and the Tongjian is best understood in conversation with it. The I Ching tradition, explored at our I Ching pillar page, provides the philosophical backdrop against which both works were written and read.

The Zizhi Tongjian is one of the most ambitious history books ever written. Its full title, 资治通鉴, translates roughly as “Comprehensive Mirror to Aid in Government,” and that title tells you exactly what Sima Guang had in mind. He was not writing a simple chronicle. He was building a mirror for rulers, a text that would let them see the consequences of political decisions across more than a thousand years of Chinese history, from the Warring States period in 403 BCE through the end of the Five Dynasties in 959 CE.

The scale is almost impossible to overstate. The Zizhi Tongjian covers 1,362 years of history in 294 chapters (juan, 卷), running to roughly three million Chinese characters. To put that in perspective, it is longer than the entire Shiji by a factor of three, and the Shiji itself was already considered monumental. Sima Guang spent nineteen years on it, from 1065 to 1084, working with a team of assistant historians who gathered and organized the primary sources before he wrote the final narrative.

Why Sima Guang Wrote It

Sima Guang (司马光, 1019 to 1086) was a Northern Song dynasty official, historian, and political figure. He served the Song court in various capacities, and he was deeply involved in the political debates of his time. The Northern Song was a period of tension between two factions: the reformers, led by Wang Anshi, who wanted to restructure the government and economy, and the conservatives, led by Sima Guang himself, who believed that the existing systems needed to be maintained and understood rather than overhauled.

The Zizhi Tongjian was, in a sense, Sima Guang’s political argument rendered as history. He believed that rulers needed to understand the past to govern wisely in the present, and he was disturbed by what he saw as a failure of emperorship in his own time. Emperor Shenzong, who supported Wang Anshi’s reforms, was intelligent but impulsive. Sima Guang wanted to give rulers a tool that would let them see, across centuries, how impulsive decisions and structural overhauls had played out in practice.

But that political motivation is only part of the story. Sima Guang was also a genuine historian, and he was frustrated with the state of historical writing in his time. The dynastic histories (the official histories of each dynasty) were written in biographical and thematic sections that made it difficult to trace the flow of events over time. If you wanted to understand what happened in the year 200 BCE, you had to piece together fragments from the basic annals, the biographies, and the treatises. Sima Guang wanted a single, chronological narrative that would let a reader follow the story of Chinese politics year by year, without jumping between different sections of a dynastic history.

That chronological structure is the Zizhi Tongjian’s most important contribution. The Shiji, for all its literary brilliance, organizes its material by genre: annals, tables, treatises, hereditary houses, and biographies. The Zizhi Tongjian organizes everything by year, month, and day. If you want to know what was happening across all of China in the spring of 260 CE, you read one paragraph. That simplicity, after a thousand years of scattered historical writing, was revolutionary.

Sima Guang submitted the first completed portions to Emperor Shenzong in 1067, and the emperor awarded the work its name: Zizhi Tongjian, the “comprehensive mirror” that would guide governance. The emperor also granted Sima Guang access to the imperial library and the resources to hire assistants, which he put to immediate use. The project consumed the rest of his career.

The Team Behind the Work

Sima Guang did not work alone. He assembled a team of three principal assistants, each responsible for a different period of history: Liu Shu (刘恕) for the pre-Tang period, Liu Ban (刘攽) for the Tang period, and Fan Zuyu (范祖禹) for the post-Tang period through the Five Dynasties. Each assistant gathered the relevant primary sources, organized them chronologically, and produced rough drafts that Sima Guang then refined and wove into a single narrative.

The team’s working method was meticulous. Before writing anything, they compiled what they called “long drafts” (chungao, 长编), which were chronological collections of every relevant passage from every available source. Sima Guang’s instruction to his assistants was clear: gather everything first, do not skip obscure accounts, and do not evaluate until you have the full picture. Only after all the evidence was assembled did he begin the work of writing the final narrative, choosing between conflicting accounts and adding his own evaluative comments.

The long drafts themselves were massive. Liu Shu, who was responsible for the pre-Tang period, reportedly produced drafts that were several times longer than the final text would be. Sima Guang cut, consolidated, and polished, but the underlying research represented the most thorough collation of Chinese historical sources that had ever been attempted.

The Time Period Covered

The Zizhi Tongjian begins in 403 BCE, the year that the state of Jin was formally divided into three separate states (Han, Zhao, and Wei), which Sima Guang saw as the moment when the Zhou feudal order broke down and the Warring States period began in earnest. It ends in 959 CE, the last year before the founding of the Song dynasty. Between those two dates, the text moves through the Warring States, Qin, Western Han, Eastern Han, Three Kingdoms, Western Jin, Eastern Jin, Southern and Northern Dynasties, Sui, Tang, and the Five Dynasties and Ten Kingdoms.

That is a staggering range. The Shiji, by comparison, covers from the legendary Yellow Emperor through Sima Qian’s own time in the Western Han. The Zizhi Tongjian starts later but goes much further forward, covering roughly three times the span of actual recorded history. Sima Guang chose to begin with the Warring States because he believed that was when political governance became systematic enough to be studied as a continuous story. Earlier periods, in his view, were too mythologized or too sparsely documented to serve as a reliable mirror for rulers.

The decision to end in 959 CE was also deliberate. Sima Guang was living under the Song dynasty, and writing about the current ruling house would have been politically dangerous and historically unreliable. By ending at the Five Dynasties, he maintained a safe historical distance while still providing his intended audience with a continuous narrative that ran right up to the dynasty they lived in.

The Structure of the Text

Each chapter (juan) of the Zizhi Tongjian covers a block of years, and within each chapter, the text is organized strictly by year and month. Events are narrated in chronological order, regardless of which dynasty or region they pertain to. This means that a single paragraph might describe events in the Han court, a rebellion in the western provinces, and a diplomatic exchange with a northern kingdom, all happening in the same season.

Sima Guang also used a technique called “matter-of-fact narration” (叙事), which means he kept his own opinions out of the main text and instead placed his evaluative comments in a separate format called “minister Guang says” (臣光曰). These comments appear at the end of significant episodes, and they carry the moral and political lessons that Sima Guang wanted his readers to draw from the history. This separation of narrative and commentary was a major innovation, and it allowed the Zizhi Tongjian to serve both as a factual record and as a work of political philosophy.

The Liang Ji Commentary

One of the most important features of the Zizhi Tongjian is its system of commentary. Sima Guang included notes throughout the text, marked by the word “臣光曰” (your minister Guang says), where he offered his assessment of the events being narrated. These are not footnotes in the modern sense. They are deliberate moral and political judgments, often sharp and specific, designed to tell the reader what lesson the preceding story carries for a ruler.

In one famous passage, Sima Guang reflects on the fall of the Wei kingdom at the hands of the Sima clan (who later founded the Jin dynasty). He notes that the Sima clan’s usurpation was, in a sense, a repetition of the Cao family’s own usurpation of the Han throne two generations earlier. The lesson, he writes, is that a regime built on force and cynicism eventually becomes the victim of the same methods used to create it. Those evaluative comments are what make the Zizhi Tongjian a mirror, not just a history.

For readers approaching the text today, the “minister Guang says” passages are often the most rewarding parts. They show a brilliant political mind working through the patterns of history, and they offer a window into how a Song dynasty intellectual understood the relationship between past and present. Whether or not you agree with every judgment, the consistency and directness of the commentary gives the Zizhi Tongjian a character that distinguishes it from every other Chinese historical text.

The Sources and the Method

Sima Guang and his team drew on an extraordinary range of sources. The extant historical record for the period they covered included not only the official dynastic histories (the Hanshu, Hou Hanshu, Sanguozhi, and others) but also private historical writings, memorials to the throne, biographical collections, and administrative documents. Where the official histories disagreed, Sima Guang had to choose. Where they were silent, he had to fill gaps from secondary sources. And where the sources contradicted each other on chronology, he had to adjudicate.

This adjudication is one of the underappreciated aspects of the Zizhi Tongjian. Sima Guang did not simply copy or summarize. He compared, evaluated, and in many cases corrected errors in the official histories. His notes frequently explain why he chose one account over another, and those explanations reveal a sophisticated historical method. He prioritized eyewitness accounts over later retellings, official records over private memoirs, and internally consistent narratives over dramatic ones that contained logical contradictions.

One example involves the death of Emperor Wan of Liang (梁武帝), who died in 549 CE after being confined and starved during the Hou Jing Rebellion. The official history records his last words as a bitter remark about the failings of his sons. Sima Guang, citing a different source, records a simpler scene: the old emperor, hungry and forgotten, murmuring something about the taste of honey (perhaps referring to a traditional remedy for starvation) as his final breath. Sima Guang chose this version because the source was closer in time to the event and because the bitter-remark version felt like a later editorial gloss inserted for dramatic effect.

The Warring States Period (403 to 221 BCE)

The Zizhi Tongjian opens with the division of Jin in 403 BCE, and its first section covers the Warring States period through the unification of China by Qin Shi Huang in 221 BCE. This is a period of intense military competition, diplomatic maneuvering, and philosophical ferment. Seven major states (Qin, Qi, Chu, Yan, Han, Zhao, and Wei) vied for dominance, and the period produced some of the most famous strategic thinking in Chinese history, including the diplomatic strategies of Su Qin and Zhang Yi and the military campaigns that eventually gave Qin the advantage.

Sima Guang’s account of this period draws heavily on the Zhan Guo Ce ( 战国策, the Strategies of the Warring States), a collection of diplomatic speeches and political anecdotes. He also draws on the Shiji and the Hanshu, but the Warring States period is the one section of the Zizhi Tongjian where the official histories are thinnest, and Sima Guang had to rely more on non-official sources.

The lesson Sima Guang draws from the Warring States is consistent and pointed: when the feudal order breaks down and states operate purely on self-interest, the result is escalating violence that consumes everyone, including the eventual winner. Qin won, but Qin’s victory was so costly and so morally destructive that the dynasty collapsed within fifteen years of unification. The commentary here is some of the sharpest in the entire text.

The Qin and Han Period (221 BCE to 220 CE)

The second major section covers the Qin dynasty (221 to 206 BCE) and the two Han dynasties (Western Han, 202 BCE to 9 CE, and Eastern Han, 25 to 220 CE). This is the period where the Chinese imperial system took shape, and Sima Guang’s account is rich with the political lessons he most wanted to convey. The Qin collapse, the rise of Han Liu Bang, the reign of Emperor Wu, the Wang Mang interregrum, and the restoration of the Han under Emperor Guangwu are all narrated in detail.

What makes this section particularly valuable is Sima Guang’s willingness to challenge the official narratives. The Han dynasty official histories, particularly the Hanshu, were written under Han sponsorship and tended to flatter the founding emperors and minimize the failures of the imperial system. Sima Guang, writing under the Song dynasty with no personal stake in the Han’s reputation, could be more honest. He shows the cost of Emperor Wu’s expansionist wars, the corruption of the eunuch factions at the Eastern Han court, and the structural weaknesses that led to the Yellow Turban Rebellion and the eventual collapse of Han authority.

The Han section also contains some of the most memorable biographical material in the Zizhi Tongjian. The text gives substantial space to figures like Dong Zhuo (whose tyranny illustrates what happens when military force enters the capital), the loyal administrator Xun Yu (whose death by forced suicide shows the limits of loyalty in a corrupt system), and the scholar-official Zheng Xuan (whose dedication to classical learning represents the enduring value of education even in political chaos).

The Three Kingdoms and Jin (220 to 420 CE)

The next section covers one of the most famous periods in Chinese history: the fall of Han, the Three Kingdoms (Wei, Shu, and Wu), the brief unification under Western Jin, and the southward retreat of Eastern Jin as northern China fragmented into competing states. This is the period that the novel Romance of the Three Kingdoms later dramatized, and for many readers, the Zizhi Tongjian’s account of this period is the entry point to the work.

Sima Guang’s narration of the Three Kingdoms is notably even-handed. The novel makes Liu Bei the hero and Cao Cao the villain. The Zizhi Tongjian, while not blind to Cao Cao’s ruthlessness, presents him as a brilliant and effective administrator whose policies stabilized northern China. Liu Bei is treated with respect but not romanticized. Sima Guang’s interest is not in hero-worship or moral theater. It is in governance: who ruled more effectively, who built more durable institutions, and whose vision of statecraft had the longer-lasting impact.

The commentary on the fall of Shu is particularly clear-eyed. Sima Guang notes that Shu fell not primarily because of Cao Wei’s military superiority but because the Shu government, under the later leadership of Jiang Wei, prioritized military campaigns over domestic administration. The state exhausted itself trying to conquer territory it could not hold, while neglecting the economic and administrative foundations that would have made it sustainable. The lesson for a ruler: do not let military ambition outrun your economic base.

Chapter 3: The Founding of the Song Dynasty

The Zizhi Tongjian opens its narrative with the Warring States period (403-221 BCE), but the text itself was written during the Northern Song dynasty, and the gravest moral question Sima Guang wrestled with was how the Song’s own founding sat in the long arc of Chinese history. The dynasty was established in 960 CE by Zhao Kuangyin, known posthumously as Emperor Taizu, in a sequence of events that were politically convenient and morally uncomfortable.

The story, as Sima Guang would have known it, went like this. Zhao Kuangyin was a senior military commander serving the Later Zhou, one of the short-lived dynasties that cycled through northern China during the Five Dynasties period. In early 960, the young Later Zhou emperor dispatched Zhao to counter an alleged Liao invasion. The army marched north, stopped at Chenqiao, a post station outside the capital, and during the night the officers supposedly draped an imperial yellow robe over the sleeping commander. Whether Zhao was genuinely surprised or had arranged the whole thing is a question the sources do not answer cleanly. He accepted the throne, returned to the capital, and the child emperor abdicated. The Liao invasion, conveniently, never materialized.

Sima Guang does not narrate the Chenqiao incident directly in the Tongjian, since his text ends in 959 CE, the year before the Song founding. But the moral framework he applies to earlier usurpations reads as a commentary on his own dynasty’s origins. When he describes Wang Mang’s seizure of the Han throne, or the military coups of the Southern and Northern Dynasties, he is establishing a standard: legitimate rule comes from moral authority, not from military convenience. The implicit question is whether the Song, which came to power through a military mutiny, could claim the Mandate of Heaven in good conscience.

The answer Sima Guang constructs through his editorial choices is nuanced. He does not deny the Song its legitimacy, but he makes clear that legitimacy must be earned through governance, not merely claimed through force. The early Song emperors, especially Taizu and his brother Taizong, did earn it: they reunified most of China, reduced military power at the court, established civil examination systems, and promoted a culture of scholarship that was arguably unmatched in world history up to that point. But Sima Guang’s governance-focused chronicle reminds the reader that legitimacy is a standing obligation, not a one-time grant.

The Mandate of Heaven is not a title deed. It is a performance review that never ends.

The Problem of Military Power

The Five Dynasties period (907-960 CE) was a brutal lesson in what happens when military power is not subordinated to civil authority. In fifty-three years, five dynasties rose and fell in the north, each founded by a military commander who overthrew the previous one. Emperor Taizu of Song, having come to power through exactly that mechanism, was determined to break the cycle.

The most famous policy decision of his early reign was the reduction of military power, encapsulated in the tradition of the “cup of wine releasing military power” (杯酒释兵权). According to later accounts, Taizu invited his senior generals to a banquet, praised their service, and then suggested that they retire to comfortable estates, surrendering their commands. Whether this happened as described or is a later embellishment, the policy was real: the Song systematically shifted governance from military to civilian hands, expanded the examination system, and placed文人 scholars above generals in the court hierarchy.

Civil Service and the Examination System

The Song expansion of the civil service examination was one of the most consequential institutional decisions in Chinese history. The jinshi degree, awarded through competitive exams based on the Confucian classics, poetry composition, and policy essays, became the primary path to government office. Taizu’s successors, especially Emperor Taizong, dramatically increased the number of examination graduates appointed each year, creating the largest civilian bureaucracy the world had seen.

Sima Guang was himself a product of this system. He passed the jinshi examination at an exceptionally young age and entered government service through the standard pathway. His career illustrates both the strengths of the examination system (it promoted talent across regions and social classes) and its tensions (it created an official class that sometimes prioritized textual mastery over practical governance).

The Tongjian, in its treatment of earlier dynasties, repeatedly demonstrates that recruitment systems matter. When the Han promoted capable administrators regardless of background, the government functioned well. When later dynasties fell back on hereditary privilege or military appointment, governance deteriorated. The Song examination system was the most developed version of the meritocratic principle, and Sima Guang’s chronicle serves, among other things, as a long argument for its value.

The Fiscal State

The Song was also China’s most commercially developed dynasty before the modern era. The government operated a sophisticated fiscal system that included paper money (the earliest in world history), state monopolies on salt, tea, and wine, and a commercial tax network that revenues from urban trade. The economic flourishing of the Song is sometimes called China’s “medieval economic revolution,” and the surplus it generated funded both the civil bureaucracy and the military defense against northern rivals.

Sima Guang, as a fiscal conservative, had complicated views on this. He recognized that the state needed revenue to function and defend itself, but he opposed what he saw as excessive extraction. His most famous political opponent was Wang Anshi, the New Policies reformer who dramatically expanded state intervention in the economy. The Tongjian, while primarily a historical work, carries an implicit argument about fiscal moderation: governments that tax responsibly and spend prudently endure; those that overreach create the very rebellions they fear.

Scholarship and the Culture of History

The Northern Song produced one of the most remarkable concentrations of intellectual talent in Chinese history. Men like Ouyang Xiu, Su Shi, Wang Anshi, Sima Guang, and Cheng Hao were more than administrators. They were literary masters, historians, philosophers, and reformers, often in bitter disagreement with one another but operating within a shared intellectual culture that valued learning above all.

The writing of history was itself a form of political action. By narrating the past, scholars made arguments about the present. Sima Guang’s choice to write a comprehensive chronicle, rather than a dynastic history focused on a single reign or house, was itself a statement: the lessons of history are universal, not proprietary to one dynasty. The Tongjian was designed to be read by rulers and officials of any era, including and especially his own.

This culture of historical consciousness is one of the most distinctive features of Chinese political thought. The Roman historian Livy wrote that the study of history offers “examples of every kind of behavior.” Sima Guang would have agreed, but with a stronger emphasis on the moral dimension: history is not just a collection of examples. It is a mirror in which the present can see itself honestly, if it has the courage to look.

Chapter 4: The Reunification of China

After the Chenqiao mutiny and the establishment of the Song in 960, Emperor Taizu faced a fragmented China. The south was divided among several regional kingdoms that had survived the collapse of the Tang, each with its own military, its own bureaucracy, and its own ambitions. The north was menaced by the Liao (Khitan) empire, a powerful nomadic state that controlled the strategically critical Sixteen Prefectures, a strip of territory that included modern-day Beijing and its surroundings. Reunification was not a given. It was a project that required military strategy, diplomatic patience, and the willingness to accept that some territories might never be recovered.

Taizu’s approach, which Sima Guang would have studied closely, was methodical. He adopted the strategy often summarized as “first south, then north” (先南后北): eliminate the southern kingdoms one by one, absorb their resources and populations, and then deal with the northern threat from a position of consolidated strength. The sequence was deliberate and reflected a realistic assessment of Song military capacity relative to the Liao.

The Southern Conquests

Between 963 and 979, the Song systematically absorbed the southern states. The process was not uniformly violent. Some kingdoms, recognizing the inevitable, submitted with negotiated terms that preserved their elites’ status and property. Others resisted and were conquered by force. The result was a China unified under a single central government for the first time since the collapse of the Tang in 907, a period of over fifty years of fragmentation.

The conquest of the Southern Tang was the most significant of these campaigns. The Southern Tang, centered on the Yangtze delta, was the wealthiest and most culturally sophisticated of the southern states. Its last ruler, Li Yu, was one of the greatest lyric poets in Chinese literary history, a man whose talent for words far exceeded his talent for governance. The Song siege of his capital at Jinling (modern Nanjing) in 974-975 was a protracted affair that ended with Li Yu’s capture and removal to Kaifeng, where he lived out his remaining years as a captive with an empty title.

Sima Guang’s treatment of Li Yu in the Tongjian, while focused on the earlier Five Dynasties period, reflects the broader lesson this episode illustrated: cultural refinement without political and military competence is a luxury that a state cannot afford indefinitely. The Southern Tang was a center of poetry, painting, and learning, and it was conquered by a state that prioritized military and administrative effectiveness. The Tongjian’s many accounts of sophisticated courts falling to harder, more practical rivals reinforce this theme repeatedly.

The brush can describe the fall of a kingdom. It cannot prevent it.

The Northern Problem: The Sixteen Prefectures

The one territorial goal that eluded both Taizu and his successor Taizong was the recovery of the Sixteen Prefectures. This strip of northern territory, ceded to the Khitan Liao empire in 936 by the Later Jin founder Shi Jingtang (who needed Liao military support to seize power), included the area around modern Beijing. Its loss was a strategic catastrophe for any Chinese dynasty based in the north. Without the Sixteen Prefectures, there was no natural defensive barrier against nomadic incursions from the steppe. The Great Wall, which ran through or near this territory, was effectively in Liao hands.

Emperor Taizong launched a major campaign to recapture the Sixteen Prefectures in 979, immediately after completing the southern reunification. The campaign failed. The Song army was defeated at the Battle of Gaoliang River (near modern Beijing), and Taizong himself reportedly fled the field on a mule cart. A second major campaign in 986 also ended in failure, with the Song forces defeated in detail by Liao cavalry.

The Treaty of Chanyuan (1005)

The unresolved northern frontier finally stabilized, after a fashion, with the Treaty of Chanyuan in 1005. The Liao had launched a deep raid into Song territory, reaching as far as the Yellow River and threatening the capital at Kaifeng. Emperor Zhenzong, on the advice of his chancellor Kou Zhun, personally took the field to rally the troops. A negotiated settlement was reached: the Song would pay an annual tribute of silver and silk to the Liao, and both sides would recognize the existing boundary.

The treaty was controversial. Many officials saw the annual payments as humiliating, a confession of weakness. Others, including those who took a longer view, recognized that the treaty bought more than a century of peace on the northern frontier, allowing the Song to develop its economy and culture without the constant drain of border warfare. Sima Guang, writing decades later, treated the treaty as a necessary evil: preferable to endless war, but a reminder that the failure to secure the Sixteen Prefectures had imposed a permanent cost on the dynasty.

The Chanyuan settlement is one of those historical moments that the Tongjian’s methodology illuminates especially well. By placing it in the context of centuries of Chinese-nomadic relations, from the Han-Xiongnu treaties through the Tang-Turk negotiations, Sima Guang shows that the Song’s predicament was not unique. Every major dynasty had faced the problem of how to manage nomadic powers that the agrarian Chinese state could not decisively defeat. The solutions varied: marriage alliances, tributary payments, military campaigns, defensive walls. Each had costs and benefits, and the Tongjian’s contribution was to lay out those trade-offs systematically so that future officials could make informed choices rather than repeating the mistakes of the past.

The Meaning of Reunification

The Song reunification of 960-979 was incomplete by the standards of the Tang or the Han. The Sixteen Prefectures remained in Liao hands, the northwest was lost to the Tangut Western Xia, and the dynasty would never control the full extent of Tang-era territory. But it was nonetheless a transformative achievement. After fifty years of fragmentation, the core of Chinese civilization, the agricultural heartland from the Yangtze delta to the Yellow River, was under a single administration. The population recovered, commerce expanded, and the conditions for the Song cultural flowering were established.

Sima Guang’s assessment of reunification, as reflected in the Tongjian’s editorial choices, was that unity matters but is not sufficient. A unified state that governs well can endure for centuries. A unified state that governs poorly can collapse faster than a fragmented one. The Tongjian spends far more time on governance than on military conquest, and that ratio is itself a statement about what Sima Guang believed determined the fate of dynasties.

The history of reunification also reinforced the Tongjian’s central methodological point: that events must be understood in sequence. The Song did not emerge from nowhere. It was the product of the Five Dynasties collapse, which was the product of the An Lushan rebellion’s damage to the Tang, which was the product of Tang military restructuring, and so on back through the centuries. To understand why the Song was what it was, you had to understand the chain of causation that produced it. That is why the Tongjian is not a history of the Song. It is a history of everything that led to the Song’s world.

The Southern and Northern Dynasties (420 to 589 CE)

The period that Sima Guang called the Southern and Northern Dynasties is one of the most complex chapters in the Zizhi Tongjian, and it is also one of the most instructive for his central argument about governance. After the collapse of the Western Jin in 316 CE, China split into two halves that would remain politically divided for nearly three centuries. The south saw a succession of short-lived dynasties (Liu Song, Southern Qi, Liang, and Chen) centered on Jiankang, modern Nanjing. The north saw a rotating cast of states established by non-Han peoples, most notably the Northern Wei under the Tuoba clan, which dominated the north for over a century before itself splitting into Eastern and Western Wei.

For Sima Guang, this period was a case study in what happens when political legitimacy fractures. The south claimed to be the legitimate successor of the Han and Jin, preserving Chinese cultural and political traditions in exile. The north, ruled by peoples who had adopted Chinese administrative systems but retained distinct cultural identities, made its own claims to legitimacy. The Tongjian’s treatment of this period is even-handed in its narration but pointed in its commentary: Sima Guang does not simply side with the south. He evaluates each ruler on the quality of their governance, not their ethnic identity or their genealogical claims.

The Northern Wei and Cultural Transformation

The Northern Wei (386 to 534 CE) is one of the most fascinating states in the Tongjian’s narrative. Founded by the Tuoba, a Xianbei (proto-Mongolic) people, it began as a typical steppe confederation but evolved into a Chinese-style imperial state. The turning point came under Emperor Xiaowen (r. 471 to 499), who initiated a sweeping program of sinicization: the court adopted Chinese language, dress, surnames, and administrative practices. The Tuoba ruling family changed its name to Yuan. Intermarriage between Xianbei and Han elites was encouraged. The capital was moved from Pingcheng (modern Datong) to Luoyang, the ancient center of Chinese civilization.

Sima Guang’s assessment of Xiaowen’s reforms is nuanced. He recognized that cultural integration was necessary for a non-Han dynasty to govern a predominantly Han population effectively. But he also noted the costs: the sinicization program alienated traditional Xianbei military elites, who felt their identity was being erased, and it weakened the martial spirit that had made the Northern Wei powerful in the first place. After Xiaowen’s death, the dynasty split into Eastern Wei and Western Wei, and the old military aristocracy reasserted itself. The lesson Sima Guang draws is that cultural policy, like all policy, has trade-offs that only become visible over time.

The Northern Wei’s Buddhist patronage is another theme the Tongjian explores extensively. The dynasty built massive cave temples at Yungang (near the old capital at Pingcheng) and Longmen (near Luoyang), and Buddhist institutions became enormously wealthy and powerful. Sima Guang, writing from a Confucian perspective, was critical of the way Buddhist monasteries drained resources from the state. Monks did not pay taxes, monasteries accumulated land, and the diversion of wealth into religious construction struck him as a governance failure. His commentary on the Liang dynasty’s Emperor Wu, who was so devoted to Buddhism that he personally entered a monastery and had to be ransomed by his court, is one of the most biting passages in the entire Tongjian.

The South: Cultural Brilliance and Political Weakness

The southern dynasties present a different set of lessons. The Liu Song (420 to 479) was militarily aggressive and briefly threatened to retake the north, but its later rulers were notorious for familial violence and political instability. The Southern Qi (479 to 502) lasted barely twenty-three years. The Liang (502 to 557) under Emperor Wu enjoyed a long period of peace and cultural flourishing before the catastrophic Hou Jing Rebellion destroyed everything. The Chen (557 to 589) was the weakest of all, controlling only the lower Yangtze region until it was absorbed by the Sui.

What Sima Guang finds in the south is a recurring pattern: cultural sophistication without military and administrative competence leads to vulnerability. The southern courts produced some of the finest poetry, calligraphy, and philosophical writing in Chinese history. The literary culture of Jiankang was unmatched. But none of that cultural capital translated into effective defense when the Hou Rebellion erupted in 548 CE, or when the Sui armies massed across the Yangtze in 588 CE.

A court that can write poetry but cannot feed its soldiers has already lost, even if the enemy has not yet arrived.

The Hou Jing Rebellion (548 to 552 CE) is one of the most dramatic episodes in the Tongjian. Hou Jing was a northern general who defected to the Liang, then rebelled when he felt the court was planning to betray him. His forces captured Jiankang, besieged the palace, and eventually starved the eighty-six-year-old Emperor Wu to death. The rebellion devastated the south’s economy and population, and the Liang dynasty never recovered. Sima Guang’s narration of these events is detailed and vivid, drawing on multiple sources to reconstruct the sequence of betrayals, miscalculations, and missed opportunities that led to the catastrophe.

Why This Period Matters for the Tongjian’s Argument

The Southern and Northern Dynasties section of the Tongjian serves a specific purpose in Sima Guang’s overall design. It demonstrates, over three centuries of evidence, that political division is a military problem, yes, but it is a governance problem. The south had legitimacy claims and cultural prestige but could not translate those into effective rule. The north had military strength but struggled with the question of how to govern a diverse population without losing the cohesion that made it strong. Neither side solved the problem, and the result was centuries of instability that ended only when the Sui reunified China in 589 CE.

For rulers reading the Tongjian, the Southern and Northern Dynasties offered a warning about what happens when the political system loses its capacity for self-correction. The southern dynasties kept replacing one ruling family with another, but the underlying structure never changed: a small court elite in Jiankang, powerful regional military commanders, and a population that had no stake in who sat on the throne. The northern states went through their own cycle of fragmentation and consolidation, but the Northern Wei’s attempt at structural reform showed that even well-intentioned changes can have unintended consequences. The lesson, as Sima Guang presents it, is that governance requires constant attention to the relationship between the political system and the people it serves. Neither cultural sophistication nor military power is sufficient on its own.

The Sui Unification Campaign and the Fall of the Chen (588 CE)

The reunification of China in 589 CE was one of the most consequential military operations in Chinese history, and the Tongjian’s account of it is a masterclass in how military success depends on political preparation as much as tactical execution. The Sui campaign against the Chen dynasty was not simply a matter of superior force crossing a river. It was the result of years of diplomatic isolation, economic pressure, and psychological warfare that eroded the Chen’s will and capacity to resist before a single soldier set foot on the south bank of the Yangtze.

Emperor Wen of Sui spent years preparing the ground. He established diplomatic relations with the Chen’s neighbors, cutting off potential allies. He encouraged defections from the Chen court, offering generous terms to officials willing to switch sides. He maintained a posture of peaceful intentions while steadily building a fleet and massing troops along the north bank of the Yangtze. The Chen ruler, the last emperor of the Chen dynasty, was reportedly living in a state of luxurious indifference, convinced that the Yangtze was an unbridgeable barrier and that the Sui would not dare attack.

The actual invasion, when it came, was swift. The Sui fleet, built in secret, descended the Yangtze in multiple columns. One column feinted toward the eastern approaches while the main force struck the center. The Chen defenses, undermined by years of psychological warfare and an underfunded military, collapsed rapidly. The last Chen emperor was captured, and the Sui forces entered Jiankang without significant resistance. Sima Guang’s account emphasizes the political preparation over the military details, making the point that the campaign was won before it was fought.

The Equal-Field System: Sima Guang’s Assessment

One of the most important institutional innovations of the Sui and early Tang was the equal-field system (均田制, juntian zhi). The system allocated land based on household size, with each adult male receiving a standard plot and returning it to the state upon reaching old age or death. The goal was to ensure that the farming population had access to sufficient land to feed itself and pay taxes, while preventing the accumulation of large estates by wealthy families.

Sima Guang’s treatment of the equal-field system is revealing. He recognized its theoretical merit: a land-owning peasantry is the foundation of a stable tax base and a healthy society. But he also documented the practical problems. The system required constant census updating, which was administratively costly. It was vulnerable to corruption, as local officials could manipulate land allocations. And it was undermined by demographic pressure: as the population grew, there was not enough land to distribute to everyone.

The system’s decline, which Sima Guang traces through the early Tang, illustrates the Tongjian’s recurring theme about the gap between institutional design and institutional reality. A policy that made sense under the conditions of the early sixth century, when centuries of war had created a land surplus and a population deficit, became unsustainable under the conditions of the mid-eighth century, when a century of peace had reversed both conditions. The failure to adapt the system to the changed conditions contributed to the fiscal crisis that preceded the An Lushan Rebellion.

The Two-Tax System and the Fiscal Transformation of Tang

After the An Lushan Rebellion, the equal-field system and the fubing military system were both shattered beyond repair. The Tang government, desperate for revenue and unable to administer the old land-based tax, adopted the Two-Tax System (两税法, liang shui fa) proposed by the chancellor Yang Yan in 780 CE. This system, which Sima Guang analyzes in detail, consolidated all taxes into two annual payments (summer and autumn), based on household wealth and land rather than on individual head counts.

The Two-Tax System was a pragmatic response to a crisis. It was also a fundamental shift in the relationship between the state and the economy. Under the equal-field and fubing systems, the state managed land allocation and military service directly. Under the Two-Tax System, the state extracted revenue from whatever economic activity was happening, without trying to regulate the underlying structure. This shift, which Sima Guang viewed with some unease, reflected a broader evolution: the Chinese state was moving from a command economy toward a tax-extracting state that left economic organization to private actors.

The Tongjian’s coverage of this fiscal transformation is one of its most valuable contributions to economic history. The official dynastic histories treat fiscal policy in separate treatises that are difficult to connect to the political narrative. Sima Guang’s chronological approach shows how fiscal decisions emerged from political crises, how they interacted with military events, and how their consequences rippled forward over years and decades.

The Sui Reunification (581 to 618 CE)

The Sui dynasty lasted only thirty-seven years, but its impact on Chinese history was enormous, and the Tongjian’s treatment of it is correspondingly rich. The Sui reunified China after nearly three centuries of division, built the Grand Canal that would define Chinese economic geography for a millennium, reformed the examination system that became the basis of Chinese bureaucratic recruitment, and then collapsed so completely that its successor, the Tang, spent the first decades of its existence trying to understand what had gone wrong.

The founder, Yang Jian (Emperor Wen, r. 581 to 604), was a regent for the Northern Zhou who seized power in a classic palace coup. He was ethnically Han but had deep roots in the Xianbei military aristocracy that had dominated the north for generations. His rise to power was ruthless: he killed the Northern Zhou royal family, the Yuwen, almost to the last person. Sima Guang’s commentary on this episode is characteristic. He does not condemn the act with moral theatrics. He simply notes the pattern: a regent who eliminates the old ruling family and seizes the throne is establishing a precedent that will eventually be used against his own descendants. And indeed, Yang Jian’s own son, Yang Guang (Emperor Yang, r. 604 to 618), would prove to be the dynasty’s destroyer.

Emperor Wen: The Administrator

Emperor Wen was, by most accounts, a competent and hardworking ruler. He simplified the administrative structure inherited from the Northern Zhou, reduced taxes, and implemented a census that registered a dramatic increase in taxable households. His government was lean compared to the elaborate court systems of the Southern Dynasties. He was famously frugal, refusing to allow elaborate court ceremonies and keeping the royal household’s expenses low.

The Tongjian credits Wen with reestablishing the bureaucratic norms that had eroded during the long period of division. He reinstated the Three Departments and Six Ministries system (三省六部) that would define Chinese government structure for the next thirteen hundred years. He revived the recommendation-based examination system, though it would be under the Tang that the keju (科举, imperial examination) became the primary path to official appointment. Sima Guang’s assessment is generally positive: Wen was a ruler who understood that good governance requires institutional competence, not just military strength or cultural prestige.

Emperor Yang: The Builder Who Broke His Empire

Emperor Yang is one of the Tongjian’s great cautionary figures. He was intelligent, culturally sophisticated, and genuinely ambitious in ways that were not inherently wrong. He wanted to connect north and south economically through the Grand Canal. He wanted to restore Chinese influence in the Korean peninsula and Central Asia. He wanted a capital that reflected the greatness of his reunited empire. Any one of these projects, undertaken alone and at a sustainable pace, might have succeeded. Yang attempted all of them simultaneously.

The Grand Canal construction involved hundreds of thousands of conscripted laborers. The canal itself was a transformative achievement: it linked the agricultural productivity of the Yangtze delta to the political centers of the north, enabling the grain shipments that would sustain every subsequent dynasty based in northern China. But the human cost was staggering. Sima Guang records the death toll among the laborers in stark terms, noting that disease, exhaustion, and accidents killed a significant fraction of the workforce. The canal was built, but it was built on the bodies of the people it was meant to serve.

The Goguryeo campaigns were even more disastrous. Emperor Yang launched three massive expeditions against the Korean kingdom of Goguryeo (612, 613, 615 CE), each involving hundreds of thousands of soldiers. The first campaign ended in catastrophe when the Sui army was ambushed and destroyed on the Yalu River. The second was aborted when a general rebelled back in China. The third ended in a negotiated retreat that achieved nothing. These campaigns drained the treasury, devastated the peasantry, and eroded whatever legitimacy the Sui still possessed.

The Sui built what every later dynasty needed. The Sui also showed what happens when a ruler treats the population as fuel for ambition rather than as the foundation of the state.

The Collapse

By 611 CE, rebellions were breaking out across the empire. The combination of canal construction, Korean campaigns, and the luxurious reconstruction of Luoyang and Jiangdu had pushed the population past its breaking point. Rebel leaders emerged in every province. Some were disaffected officials, others were peasant leaders, and still others were regional strongmen who saw an opportunity to carve out their own territories. The Tongjian narrates the collapse with its characteristic chronological precision, showing how the rebellion spread month by month until the central government lost control of everything except the immediate vicinity of the emperor’s court.

Emperor Yang, rather than confronting the crisis, retreated to his southern capital at Jiangdu (modern Yangzhou) and spent his final months in a state of denial and dissolution. He was assassinated in 618 CE by members of his own entourage. The Tongjian’s account of his last days is a study in how a ruler who has lost touch with reality eventually loses the ability to protect himself, even from the people closest to him.

Sima Guang’s Verdict on the Sui

Sima Guang’s evaluative comments on the Sui are among the most direct in the Tongjian. He frames the dynasty as a tragedy of competence: Yang Jian was capable, but his violent seizure of power established a moral rot that his son inherited. Yang Guang was brilliant, but his inability to pace his ambitions turned capability into catastrophe. The lesson for rulers is that good judgment is both about what you do, but about how quickly you do it, and at whose expense. A project that would be beneficial over twenty years can be destructive over five. A war that would be winnable with proper preparation can be lost when launched prematurely.

The Sui also illustrates the Tongjian’s recurring theme about the relationship between rulers and the population. The Grand Canal, the examination system, the administrative reforms, all these were genuinely valuable contributions. But they were extracted from a population that received nothing in return except heavier labor and higher taxes. Sima Guang’s view, stated and restated throughout the text, is that the population is the root of the state. A ruler who neglects the root to build branches is building something that cannot stand.

The Tang Dynasty Part 1: Founding and Golden Age (618 to 763 CE)

The Tang dynasty is the longest single section of the Zizhi Tongjian, occupying roughly a third of the entire work. This is fitting, because the Tang was the longest-lived and most influential dynasty in the period the Tongjian covers, and its history contains the full range of political episodes that Sima Guang wanted his readers to study: brilliant founding, magnificent governance, gradual institutional decay, catastrophic rebellion, and agonizing recovery. The Tongjian’s Tang section is, in many ways, the heart of the entire work.

The Founding

The Tang was founded by Li Yuan (Emperor Gaozu), a Sui general who controlled the strategic fortress of Taiyuan in Shanxi. The founding story, as the Tongjian narrates it, is one of careful calculation rather than spontaneous rebellion. Li Yuan was not the first to rebel against the Sui, and he was not the most obvious candidate for imperial power. What he had was a combination of military competence, political patience, and a talented second son, Li Shimin, who would become the real architect of Tang power.

Li Shimin (later Emperor Taizong, r. 626 to 649) is one of the Tongjian’s most studied figures. His path to the throne was violent: in 626 CE, he ambushed and killed his older brother, the crown prince Li Jiancheng, and his younger brother Li Yuanji at the Xuanwu Gate of the palace, then forced his father to abdicate. Sima Guang does not gloss over this. His commentary acknowledges the moral stain but then evaluates Taizong’s reign on its own terms, and those terms are overwhelmingly positive. The Tongjian’s treatment of Taizong is a clear example of Sima Guang’s principle that governance outcomes matter more than origin stories.

The Zhenguan Era: Governance as a Learned Skill

The Zhenguan era (627 to 649 CE), named after Taizong’s reign title, is presented in the Tongjian as the gold standard of Chinese governance. Taizong surrounded himself with capable ministers who were willing to contradict him, and he cultivated a culture of critical advice that was rare in any dynasty. His relationship with the minister Wei Zheng (魏征) is the most famous example. Wei Zheng was a former advisor to the crown prince that Taizong had killed, and Taizong appointed him specifically because he knew Wei Zheng would not hesitate to speak uncomfortable truths.

The Tongjian records dozens of exchanges between Taizong and his ministers in which the emperor is corrected, challenged, or outright contradicted, and in which he acknowledges his errors and changes course. These exchanges are not hagiography. Sima Guang includes episodes where Taizong acts badly: he loses his temper, he makes impulsive decisions, he is tempted by luxury. What distinguishes him, in the Tongjian’s account, is not perfection but the capacity for self-correction. He listens, he reflects, and he adjusts. That capacity, Sima Guang argues, is what made the Zhenguan era work.

A mirror shows you your face. A good minister shows you your mistakes. Taizong understood that the second is more valuable than the first, which is why he called his history book a mirror.

The institutional reforms of the Zhenguan era were significant. Taizong refined the examination system, creating a more regular pathway for merit-based official recruitment. He reorganized the military into the fubing (府兵) system, which integrated agricultural production with military service and reduced the state’s dependence on professional soldiers. He established clear procedures for memorial submission and court debate, ensuring that policy decisions went through a deliberative process rather than emerging from the emperor’s whim. The Tongjian narrates each of these reforms in detail, showing how they were implemented and what their effects were.

Expansion and the Frontier

Under Taizong and his successor Gaozong (r. 649 to 683), the Tang expanded its influence dramatically. The Eastern Turks were defeated in 630, making Taizong the “Heavenly Khan” (天可汗) to the steppe peoples. The Western Regions were brought under Tang influence through a combination of military campaigns and diplomatic marriages. Tang authority extended into Central Asia further than any previous Chinese dynasty, and the Silk Road trade flourished under the relative security that Tang garrisons provided.

Sima Guang’s treatment of Tang expansion is balanced. He acknowledges the benefits of frontier security and trade, but he is wary of overextension. The Tongjian includes several passages where ministers warn against costly campaigns in distant territories, and Sima Guang’s commentary frequently notes that the same expansion that brought glory also created military commitments that the treasury would struggle to sustain. The seeds of the An Lushan Rebellion, in the Tongjian’s telling, were planted during the very period of Tang greatness.

Empress Wu Zetian

The reign of Wu Zetian (690 to 705 CE), the only woman to rule China in her own name, is one of the Tongjian’s most complex sections. Wu was a concubine of Taizong who became the empress of Gaozong, gradually took over the administration during Gaozong’s illness, and eventually declared her own dynasty, the Zhou, interrupting the Tang for fifteen years. Sima Guang’s evaluation is characteristically measured: he condemns her methods (she was ruthless in eliminating political opponents, including members of her own family) but acknowledges her administrative competence. Under her rule, the examination system was expanded, capable officials were promoted, and the empire remained largely stable.

The Tongjian’s treatment of Wu Zetian illustrates Sima Guang’s commitment to evaluating governance rather than personalities. He does not moralize about a woman holding power. He evaluates her on the same criteria he applies to every ruler: Did the state function well? Were capable people promoted? Were the people’s burdens manageable? By those criteria, Wu Zetian’s reign was competent, if morally compromised. Sima Guang reserves his sharpest criticism for the terror she employed against potential rivals, not for her gender or her ambition.

The High Tang Under Xuanzong

Emperor Xuanzong (r. 712 to 756) presided over the peak of Tang culture and power, and also over its near-destruction. His early reign, known as the Kaiyuan era (713 to 741), is often described as the most prosperous period in all of Chinese imperial history. The empire was at its maximum extent, the capital at Chang’an was the largest city in the world, poetry and painting reached extraordinary heights, and the economy was vibrant. The Tongjian narrates this period with a sense of looming dread, because Sima Guang knows what is coming.

The turning point, as the Tongjian presents it, was Xuanzong’s growing reliance on Li Linfu, a chancellor who monopolized power by systematically eliminating capable rivals and telling the emperor only what he wanted to hear. After Li Linfu’s death, Xuanzong placed his trust in Yang Guozhong, an even more incompetent figure whose feud with the frontier general An Lushan created the conditions for rebellion. Sima Guang’s commentary on this sequence is devastating: a ruler who stops listening to critical advice has begun the process of self-destruction, regardless of how much prosperity surrounds him.

The Tang Legal Code and the Foundations of Chinese Jurisprudence

The Tang dynasty produced one of the most influential legal codes in world history: the Tanglu Shuyi (唐律疏议, the Tang Code with Commentary). This code, completed in 653 CE under Emperor Gaozong, established the legal framework that would influence every subsequent Chinese dynasty and spread to Korea, Japan, and Vietnam. Sima Guang’s treatment of the Tang legal system, while not as extensive as his coverage of political events, reflects his understanding that legal institutions are the infrastructure of governance.

The Tang Code organized Chinese law into a structured hierarchy of offenses and penalties, with clear gradations based on severity, intent, and the social status of both perpetrator and victim. It distinguished between intentional and unintentional acts, provided mitigating circumstances, and established procedures for investigation, trial, and appeal. The commentary that accompanied the code provided interpretive guidance that made the system remarkably consistent and predictable for its time.

Sima Guang’s references to legal processes in the Tongjian reveal how the code worked in practice, not just in theory. He records cases where officials misused the legal system for political purposes, cases where the code’s protections were circumvented by powerful interests, and cases where the system functioned as designed, producing just outcomes. These concrete examples enrich our understanding of Tang governance in ways that the legal treatise alone cannot provide.

The Tang Examination System: Merit and Its Limits

The Tang examination system (科举, keju) was the institutional innovation that most directly shaped the political culture of the Tongjian’s era and of every subsequent Chinese dynasty. Under the Tang, the exam system evolved from a supplementary recruitment method into an important pathway to official appointment, though it never achieved the dominance it would have under the Song. The Tang still relied heavily on recommendation, hereditary privilege, and military service to fill its bureaucracy.

The most important examination during the Tang was the jinshi (进士, advanced scholar) degree, which tested literary skill, political knowledge, and classical learning. The jinshi graduates formed an increasingly distinct social and political group, one that would eventually challenge the old aristocratic families for dominance at court. Sima Guang’s political context is relevant here: he was himself a jinshi graduate from a prominent academic family, and the Tang examination politics that the Tongjian documents were, in many ways, the origin of the Song political culture that Sima Guang participated in himself.

The exam system was not just a way to select officials. It was a way to define what it meant to be educated, to be qualified, to be capable of governance. That definition, once established, endured for over a thousand years.

The Tongjian records several episodes where examination graduates used their literary credentials to challenge aristocratic officials, and where the tension between meritocratic and hereditary routes to power shaped court politics. The most famous of these was the Niu-Li factional struggle of the ninth century, which pitted examination graduates (associated with the Niu faction) against aristocratic families (associated with the Li faction). Sima Guang, who had his own factional struggles with the reform camp, presents the Niu-Li conflict as an example of how factional identity, once established, can paralyze government for decades.

Tang Foreign Relations: The Silk Road and the Tributary System

The Tang dynasty was remarkable for its openness to foreign trade, religion, and cultural exchange. The Silk Road, which connected Chang’an to Central Asia, Persia, and the Mediterranean, flourished under Tang protection. Foreign merchants, monks, and diplomats made Chang’an one of the most cosmopolitan cities in world history. The Tongjian’s references to foreign relations, while not concentrated in a single section, appear regularly throughout its Tang coverage and provide a running account of how the dynasty managed its relationships with the outside world.

The tributary system (朝贡, chaogong) was the formal framework for Tang foreign relations. Neighboring states and peoples sent periodic missions to Chang’an, offering goods and acknowledging Tang superiority in exchange for trading privileges, diplomatic recognition, and sometimes military support. The system was more theater than coercion: in many cases, the Tang gave more in return gifts than it received in tribute. The political value of the system lay in the symbolic recognition it provided, and in the trade networks it facilitated.

Sima Guang’s assessment of the tributary system is measured. He acknowledges its role in maintaining stable relations with neighbors, but he is wary of its costs. The Tang’s engagements with the Western Turks, the Tibetan Empire, and the Uighur Khaganate involved substantial military and diplomatic expenditures that the treasury could not always sustain. The Tongjian documents how these foreign commitments, accumulated over decades, contributed to the fiscal pressures that culminated in the An Lushan Rebellion.

The Tang Dynasty Part 2: An Lushan Rebellion and Decline (755 to 907 CE)

The An Lushan Rebellion (755 to 763 CE) is the pivotal event of the Tang dynasty, and the Tongjian’s account of it is one of the longest and most detailed narratives in the entire work. Sima Guang devoted more space to these eight years than to entire centuries of earlier history, because the rebellion exposed every structural weakness that had been accumulating during the Tang golden age and set in motion the processes that would eventually destroy the dynasty.

An Lushan and the Frontier Military System

An Lushan was a Sogdian-Turkic general who rose to prominence through the frontier military system that the Tang had developed over the previous century. As the Tang expanded, it created military provinces (fang, 防或节度使, jiedushi) along the frontiers, each commanded by a military governor with substantial autonomy. The original fubing system, which tied soldiers to agricultural land and rotated them through service, had broken down under the pressure of constant frontier warfare. By Xuanzong’s reign, frontier commanders controlled professional standing armies, collected local taxes, and administered civil government in their territories. They had become, in effect, semi-independent warlords operating under imperial commission.

An Lushan commanded three of these frontier provinces simultaneously, giving him control over the largest military force in the empire. He was able to do this because he had cultivated the trust of Emperor Xuanzong and Yang Guifei, the emperor’s favorite concubine, while concealing his ambitions behind a persona of loyal bluntness. The Tongjian records the repeated warnings that ministers sent to Xuanzong about An Lushan’s ambitions, and the emperor’s repeated refusal to believe them. Sima Guang presents this as the classic failure of a ruler who has lost the ability to distinguish honest advice from flattery.

The Fall of Chang’an

The fall of Chang’an in July 756 is one of the most dramatic scenes in the Tongjian. Xuanzong, informed that the rebel army had broken through the last defensive line, fled the capital at night with a small escort, his court, and Yang Guifei. The march westward into the mountains was a nightmare: soldiers deserting, supplies running out, the court reduced to a desperate caravan. At the Mawei post station, the escort troops refused to continue. They demanded the execution of Yang Guozhong, the chancellor they blamed for the catastrophe, and then demanded Yang Guifei’s death as well.

Sima Guang’s narration of the Mawei incident is restrained but devastating. He describes Xuanzong’s attempt to protect Yang Guifei, the soldiers’ insistence, and the final moment when the emperor ordered a eunuch to strangle her. The Tongjian does not editorialize heavily here. The events speak for themselves. A ruler who has so lost control that his own guards dictate who lives and who dies has already ceased to be a ruler in any meaningful sense.

The Tang survived the rebellion. But the Tang that survived was not the same Tang that entered it. The capital was recaptured, the rebels were defeated, and the dynasty limped on for another hundred and forty years. What it never recovered was the confidence that a centralized government could control its own military.

The Aftermath: Military Governors and Imperial Weakness

The rebellion ended in 763, but the settlement was less a victory than a negotiated stalemate. Several of the rebel generals who surrendered were allowed to keep their territories and armies in exchange for accepting Tang suzerainty. These Hebei provinces became effectively autonomous, paying only nominal tribute and choosing their own successions. The central government, unable to impose its authority, had to accept a fragmented empire in which military governors across the country operated with varying degrees of independence.

The Tongjian’s coverage of post-rebellion Tang is a chronicle of the central government’s struggle to reassert control over its own military. The fubing system was gone, replaced by professional armies whose loyalty was to their immediate commanders rather than to the throne. The fiscal system was strained by the need to maintain standing armies while tax revenues declined. Eunuch power at court grew, as emperors increasingly relied on eunuch generals to command the palace armies, creating a new power center that would eventually control the succession itself.

The Huang Chao Rebellion and Final Collapse

The Tang’s final century was punctuated by recurring rebellions, fiscal crises, and factional struggles at court. The most devastating of these was the Huang Chao Rebellion (875 to 884 CE). Huang Chao was a failed examination candidate turned salt smuggler turned rebel leader. His forces marched across China, sacking the southern port of Guangzhou (where they reportedly killed a large portion of the foreign merchant community, including Arab and Persian traders), and then turned north and captured Chang’an itself in 880 CE.

The sack of Chang’an by Huang Chao was the final blow to Tang prestige. Although the rebellion was eventually suppressed with the help of Shatuo Turk allies, the central government never recovered effective control. Regional military governors became de facto independent rulers, and the last Tang emperors were puppets controlled by whichever warlord held the capital. The dynasty was formally ended in 907 when Zhu Wen, a former Huang Chao lieutenant who had defected to the Tang, deposed the last emperor and declared the Later Liang dynasty.

Sima Guang’s commentary on the Tang collapse emphasizes the structural rather than the personal. Individual rulers made bad decisions, but the underlying problem was the inability of the central government to control the military governors it had created. The frontier military system that enabled Tang expansion in the seventh century became the instrument of its destruction in the ninth. The lesson, as the Tongjian presents it, is that institutions designed for one set of circumstances can become pathologies under another. The fubing system worked when the frontier was active and soldiers rotated between farming and fighting. It broke when the frontier became permanent and soldiers became professionals. The failure to adapt the military system to changing conditions was, in the Tongjian’s analysis, the root cause of everything that followed.

The Mawei Mutiny: A Turning Point in Chinese History

The Mawei post station mutiny deserves closer examination than any brief summary can provide, because it is one of those moments in the Tongjian where the intersection of personal relationships, military failure, and political collapse becomes visible in a single, devastating scene. The Tongjian’s account of the Mawei incident is drawn from multiple sources, and Sima Guang’s careful source comparison reveals the layers of the story in a way that no single dynastic history does.

By July 756, the situation was desperate. An Lushan’s rebel forces had broken through the Tong Pass, the last defensive position protecting Chang’an. The imperial court, its military forces scattered or defeated, was retreating westward toward Sichuan. The escort consisted of several thousand soldiers, many of them demoralized by weeks of defeats and weeks of watching their commanders flee while the empire burned. The immediate trigger for the mutiny was the presence of Yang Guozhong, the chancellor who had mishandled the relationship with An Lushan and whose policies the soldiers blamed for everything that had happened.

When Yang Guozhong was spotted meeting with Tibetan envoys, the士兵 interpreted it as a sign of further treachery. They killed him on the spot, hacked his body to pieces, and then demanded that Yang Guifei also be killed. The soldiers’ reasoning was practical: the Yang family had led the empire to ruin, and as long as Yang Guifei lived, the Yang faction retained influence over the emperor. Xuanzong, sixty-two years old and physically exhausted from days of marching, attempted to reason with the troops. The commanding general Chen Xuanli delivered the message bluntly: the soldiers would not continue until Yang Guifei was dead.

The Tongjian records what happened next with admirable restraint. Xuanzong retreated to a private moment, emerged, and ordered Gao Lishi, his most trusted eunuch, to carry out the execution. Yang Guifei was strangled. The soldiers confirmed her death and then continued the march. The entire episode took perhaps an hour. In that hour, the Tang dynasty’s golden age ended. Xuanzong would never return to Chang’an. The emperor who had presided over the most prosperous and culturally brilliant period in Chinese imperial history was reduced to commanding the murder of the woman he loved in order to preserve his own life.

Sima Guang’s commentary on Mawei is one of the most measured in the entire work. He does not moralize. He simply notes that the destruction of the Yang faction, while necessary for the military to function, was too late to change the fundamental situation. The rebellion would continue for seven more years. The real lesson, he suggests, is that the failure at Mawei began years before Mawei. It began when Xuanzong stopped listening to critical advice, when Li Linfu eliminated competent ministers, and when the court culture of the Kaiyuan era was replaced by something softer and more self-indulgent. By the time the soldiers demanded blood at a post station in the mountains, the damage was already done.

The Tongjian does not blame Yang Guifei. It blames the system that allowed a single favorite to become the emperor’s only source of truth. When the truth was too late arriving, it arrived at the point of a spear, and it demanded a life. That is the cost of institutions that protect leaders from uncomfortable facts.

The Tang Recovery Under Suzong and Daizong

After the Mawei mutiny, the Tang court split. Xuanzong continued to Sichuan while his son Suzong went north to Lingwu and declared himself emperor. The Tongjian records this succession without a formal abdication as a tense political moment: Suzong’s action was technically illegitimate, but it was necessary to establish a functioning government that could coordinate the war against An Lushan. Sima Guang’s evaluation acknowledges the constitutional irregularity while accepting the practical necessity.

The Tang recovery was a slow, grinding process that involved Chinese armies, Uighur Turk auxiliary cavalry, and a series of complex negotiations with formerly rebel commanders. The recapture of Chang’an in 757 was a significant military achievement, accomplished with the help of Uighur cavalry that the Tang had hired at a steep price. Sima Guang’s narration of the recovery campaign documents the increasing reliance on foreign military power that would become a permanent feature of late Tang governance.

Under Suzong (r. 756 to 762) and Daizong (r. 762 to 779), the court faced the problem of what to do with the military governors who had remained loyal or had switched sides during the rebellion. The practical solution was to let most of them keep their commands, which established the pattern of regional military autonomy that would define the rest of the dynasty. The Tongjian presents this as a necessary compromise: the court lacked the military power to impose its will on the governors, and attempting to do so might have driven them back into rebellion. The compromise preserved the dynasty in name while conceding much of its effective authority.

The Five Dynasties and Ten Kingdoms (907 to 960 CE)

The Five Dynasties period is the last major section of the Zizhi Tongjian, and it is the section where Sima Guang’s chronological method delivers its greatest value. The official histories of this period are a confusing mess: five separate dynastic histories, each covering a regime that lasted barely a decade or two, plus accounts of the ten independent kingdoms that coexisted in the south. Reading them in the traditional biographical format is like trying to follow five chess games played simultaneously on adjacent boards. Sima Guang’s year-by-year narrative threads them together into a single, comprehensible story.

The Five Northern Dynasties

The five dynasties that controlled the north in succession were: the Later Liang (907 to 923), Later Tang (923 to 936), Later Jin (936 to 947), Later Han (947 to 950), and Later Zhou (951 to 960). None lasted more than sixteen years. Each was founded by a military commander who seized power from his predecessor, and each was destroyed by the same method. The cycle was so predictable that Sima Guang’s commentary becomes almost formulaic: a strong commander builds a power base, eliminates the sitting dynasty, claims the throne, and within a few years faces the same challenge from his own subordinates.

The Later Liang was founded by Zhu Wen, the former Huang Chao lieutenant. He was a competent military commander but a deeply flawed ruler, known for sexual predation within his own family and for killing capable ministers who displeased him. His dynasty was destroyed by Li Keyong’s son Li Cunxu, a Shatuo Turk commander who established the Later Tang. Li Cunxu was one of the most militarily gifted figures of the period, but he was a poor administrator who alienated his own troops and was killed in a mutiny after only three years on the throne.

The Later Jin is significant for one of the most consequential decisions in Chinese diplomatic history. Its founder, Shi Jingtang, needed the support of the Liao (Khitan) empire to seize power, and in exchange he ceded the Sixteen Prefectures, a strip of northern territory that included modern Beijing. This territory would remain in non-Chinese hands for over four hundred years, until the Ming dynasty recaptured it in 1368. The cession also established a pattern of dependency: the Later Jin emperor addressed the Liao emperor as “son” and received the Liao emperor as “father,” a relationship that humiliated the Chinese court and eventually provoked Shi Jingtang’s successor to rebel, leading to a Liao invasion that destroyed the dynasty.

The Ten Kingdoms in the South

While the north cycled through five dynasties, the south was divided among ten independent kingdoms. These varied enormously in size, stability, and cultural character. The Wu Yue in the Yangtze delta was prosperous and stable, maintaining a careful diplomatic balance between the northern dynasties and the Liao. The Southern Han in Guangdong was notorious for its bizarre court practices, including requiring all officials to be castrated. The Former and Later Shu in Sichuan were culturally vibrant, producing some of the finest poetry of the period. The Southern Tang, as mentioned in the previous chapter, was a center of literary culture that fell to military force.

The Tongjian’s coverage of the southern kingdoms is necessarily less detailed than its coverage of the north, because Sima Guang’s focus is on the dynastic succession that determined who ruled the central plain. But he includes enough material to draw his central contrast: the south, despite political fragmentation, was generally more stable and prosperous than the north. Southern kingdoms maintained functioning administrations, collected taxes, and supported cultural production. The north was consumed by constant warfare, military coups, and administrative chaos. The lesson Sima Guang draws is that political stability, even in a small kingdom, produces better outcomes than constant upheaval, even in a large empire.

The Five Dynasties are fifty-three years of evidence that a political system based on raw military power is inherently unstable. Every ruler was a soldier who seized the throne. Every ruler was overthrown by another soldier. The cycle could only be broken by a system that separated military command from political legitimacy.

The Later Zhou: Reform and Foundation

The last of the five dynasties, the Later Zhou, is the most important for the Tongjian’s narrative because it set the stage for the Song founding. Its second ruler, Emperor Shizong (Chai Rong, r. 954 to 959), was a reformer who recognized that the cycle of military coups could only be broken by addressing the structural problem of military autonomy. He began to centralize military command, reduce the power of regional commanders, and build a palace army that answered directly to the throne.

Shizong also initiated economic reforms: he simplified taxation, encouraged agricultural production in war-devastated areas, and began the work of repairing the Grand Canal infrastructure. His military campaigns were targeted and effective: he pushed back the Liao in the north and consolidated Later Zhou control over the central plain. When he died suddenly at age thirty-eight in 959 CE, the throne passed to his seven-year-old son. It was against this child that Zhao Kuangyin would stage the Chenqiao Mutiny three months later.

Sima Guang’s Assessment of the Five Dynasties

The Tongjian’s evaluative comments on the Five Dynasties are among the most pointed in the entire work. Sima Guang saw this period as the ultimate vindication of his argument that legitimacy cannot rest on military force alone. Each of the five dynasties was founded by a capable military commander. Each fell because another capable military commander wanted the same thing. The cycle was not broken by a particularly virtuous or capable founder. It was broken by a structural change: the Song dynasty’s systematic demilitarization of governance, the elevation of civil officials over military commanders, and the creation of a bureaucratic system that made military coups structurally difficult.

That structural change, Sima Guang believed, was the most important lesson of the entire Tongjian. The book covers 1,362 years of history, and its argument is simple: governance matters more than conquest, institutions matter more than individuals, and the population’s welfare is the only legitimate measure of a regime’s success. The Five Dynasties period, with its rapid succession of regimes that each had military power but none of which had effective governance, is the negative proof of that argument.

The Ten Kingdoms: Southern Stability Amid Northern Chaos

While the north cycled through five dynasties in fifty-three years, the south was divided among ten kingdoms that, in most cases, enjoyed considerably more stability. The Tongjian’s coverage of the southern kingdoms is necessarily less detailed than its treatment of northern dynastic politics, because Sima Guang’s focus is on the central plain succession. But the material he does include reveals a south that was, in many ways, better governed than the north during this period.

The Wu Yue kingdom (907 to 978) in the Yangtze delta was the most economically successful. Its rulers invested in hydraulic infrastructure, including the expansion of the seawall system around Hangzhou Bay that protected the fertile coastal lowlands from tidal flooding and saltwater intrusion. The Wu Yue also maintained a careful diplomatic policy, submitting voluntarily to the Song dynasty in 978 without a fight, preserving its economic infrastructure for the benefit of the unified empire that followed.

The Former Shu (907 to 925) and Later Shu (934 to 965) in Sichuan were culturally vibrant, producing poetry, painting, and scholarly work that would influence the Song cultural renaissance. The Southern Han (917 to 971) in Guangdong was the strangest of the ten: its rulers required all officials to be eunuchs, creating a court culture that was unique in Chinese history and that the Tongjian treats with a mixture of bemusement and distaste. The Min (909 to 945) in Fujian and the Chu (927 to 951) in Hunan were smaller but dotted with productive periods.

Sima Guang’s Sources: How the Tongjian Was Built

The Tongjian’s claim to reliability rests on the extraordinary breadth of its source base. Sima Guang and his team drew on every available historical record for the 1,362 years they covered. The surviving bibliography of the Tongjian’s sources, preserved in Sima Guang’s preface and in the work’s companion volume the Kaoyi (考异, Examination of Variances), lists over three hundred separate texts.

The sources can be grouped into several categories. First, the official dynastic histories: the Shiji, Hanshu, Hou Hanshu, Sanguozhi, Jinshu, Songshu, Nan Qishu, Liangshu, Chenshu, Weishu, Beishi, Nanshi, Suishu, Jiutangshu, Xintangshu, Jiu Wudaishi, and Xin Wudaishi. Second, private historical writings: including works that are now lost or survive only in fragments, such as the various “records of the unofficial” (biji, 笔记) and the “miscellaneous histories” (zashi, 杂史) that were produced throughout the period Sima Guang covers. Third, memorials, edicts, and administrative documents preserved in compilations like the Cefu Yuangui and the Tang Hui Yao. Fourth, inscriptions, genealogical records, and local histories that provided additional information.

The Kaoyi, Sima Guang’s companion volume listing where his sources disagreed, is itself a crucial text. It documents over a thousand cases where the sources conflicted, explains which version Sima Guang chose and why, and preserves the rejected alternatives. For modern historians, the Kaoyi is invaluable: it shows the working of a historian’s mind, the reasoning behind choices that would otherwise be invisible, and the range of information that was available in the eleventh century but has since been lost.

The Tongjian’s Political Philosophy: Beyond Conservative

Labeling the Tongjian as simply conservative misses the complexity of Sima Guang’s political thought. His conservatism was not a blanket endorsement of the status quo. It was a preference for evidence-based gradualism over theory-based transformation. He recognized that institutions need to adapt to changing conditions; he simply wanted adaptation to be driven by observed outcomes rather than abstract reasoning about what should work.

Sima Guang’s evaluative comments reveal several recurring principles. First, the welfare of the population is the fundamental criterion for evaluating governance. Policies that increase the people’s burdens, regardless of their theoretical justification, are bad policies. Second, the ruler’s primary obligation is to maintain the conditions under which capable people can provide honest advice. A court where ministers tell the emperor only what he wants to hear is a court heading for disaster. Third, military power must be subordinated to civilian government. When military commanders become autonomous, the state fragments, and the population suffers the consequences. Fourth, institutional change should be gradual and reversible. Sweeping reforms that cannot be undone carry risks that their proponents typically underestimate.

These principles are not timeless truths. They are conclusions drawn from a thousand years of historical evidence. Sima Guang would be the last to claim that they apply universally. What he claims is that the evidence of the Tongjian supports these principles, and that rulers who ignored them, in the 1,362 years his text covers, generally regretted it.

The Tongjian does not offer a theory of politics. It offers a thousand years of experimental data. The theory is left to the reader, who can examine the evidence and draw their own conclusions. That, more than any particular argument the text makes, is its enduring methodological contribution.

The Tongjian and Modern Historical Method

Modern professional historians approach the Tongjian with a combination of reverence and critical distance. The reverence is for Sima Guang’s method: his source compilation, his comparison of conflicting accounts, his transparency about editorial choices, and his separation of narrative from commentary. These practices, which he developed in the eleventh century, are recognizably similar to the source-critical methods that European historians would only systematize in the nineteenth century.

The critical distance comes from recognizing that the Tongjian, for all its methodological sophistication, was written with a specific political purpose: to persuade Song dynasty rulers to adopt conservative governance. The selection of episodes, the balance of attention across periods, and the evaluative comments are all shaped by this purpose. Modern historians use the Tongjian as a primary source for the periods it covers, but they are aware that it is an interpretation, not a neutral record.

For the periods where the original sources survive, the Tongjian can be checked against its primary materials, and it generally holds up well. Sima Guang’s source criticism is careful, and when he makes editorial choices, he documents them in the Kaoyi. For periods where the original sources are lost, the Tongjian is itself effectively a primary source, sometimes the only surviving record of information that existed in the eleventh century. This makes it both an interpretation and a primary document, a dual status that makes it endlessly fascinating for historians.

Sima Guang’s Political World: The Northern Song Reform Debates

The Zizhi Tongjian cannot be fully understood without understanding the political context in which it was written. Sima Guang was not a detached scholar working in isolation. He was one of the most powerful political figures of the Northern Song dynasty, and the Tongjian was shaped by, and in turn shaped, the great political controversy of its era: the reform movement led by Wang Anshi (王安石) under Emperor Shenzong.

The Reform Faction and the Conservative Response

In 1069, Emperor Shenzong appointed Wang Anshi as vice grand councilor and gave him broad authority to implement a series of reforms known as the New Policies (新法). Wang Anshi was a brilliant and unconventional thinker who believed that the Song government was structurally inefficient and that the solution was not to return to the practices of the past but to design new institutions that would increase state revenue, stabilize prices, improve military readiness, and reduce the power of the landlord class.

The New Policies included the Green Sprouts Law (青苗法), which provided government loans to farmers at interest rates lower than private moneylenders charged; the Market Exchange Law (市易法), which established government agencies to buy and sell goods to stabilize prices; the Baojia Law (保甲法), which organized households into mutual-responsibility groups for policing and military training; and the Equal-Tax Law (方田均税法), which surveyed land to ensure that tax burdens were distributed based on actual holdings rather than outdated assessments.

Sima Guang opposed the New Policies. His opposition was not simply reactionary. He believed that the government’s role should be to maintain existing institutions, reduce expenditure, and minimize intervention in the economy. He argued that the Green Sprouts Law, whatever its stated intentions, would in practice force farmers to take loans they did not need and create a new revenue stream that the government would become dependent on. He predicted that the Market Exchange Law would crowd out private merchants and create opportunities for corruption. He warned that the Baojia system would burden rural populations with military obligations they could not fulfill.

The Tongjian as Political Argument

The Tongjian was, in a real sense, Sima Guang’s answer to Wang Anshi. Wang Anshi argued that new institutions could solve the problems of governance. Sima Guang argued that history showed, over and over, that well-intentioned institutional changes often produced unintended consequences that were worse than the problems they were designed to solve. The Tongjian is filled with examples of reformers who disrupted working systems in pursuit of improvement and produced disaster instead.

This does not mean the Tongjian is a simple conservative text. Sima Guang was perfectly willing to praise rulers who implemented effective reforms. His praise for Emperor Wen of Sui’s administrative reorganization and for Emperor Taizong of Tang’s examination reforms shows that he was not opposed to change per se. What he opposed was change driven by theory rather than evidence, change that was imposed rapidly without understanding the existing system, and change that increased the government’s extractive power over the population.

Wang Anshi wanted to build new institutions. Sima Guang wanted to understand why existing ones failed. The Tongjian is the case study for that understanding: 1,362 years of evidence about what works, what does not, and why the difference often lies in execution rather than design.

The Political Exile and the Writing

When the reform faction held power, Sima Guang was effectively exiled from the capital. He spent fifteen years (1071 to 1085) in Luoyang, away from the center of government, and it was during this period of political marginalization that he completed the bulk of the Tongjian. This is not a coincidence. The work that became the greatest history book in the Chinese tradition was written by a man who had lost the political argument and turned to history to make the case he could no longer make in the halls of power.

In 1085, Emperor Shenzong died, and the young Emperor Zhezong ascended the throne under the regency of Empress Dowager Gao, who was sympathetic to the conservative faction. Sima Guang was recalled to the capital and appointed grand councilor. He spent the last year of his life (1085 to 1086) dismantling Wang Anshi’s reforms with the same energy he had devoted to writing the Tongjian. He died in 1086, shortly after completing the repeal of the New Policies.

What the Political Context Tells Readers Today

Understanding the political context of the Tongjian’s creation helps modern readers in two ways. First, it explains the text’s emphasis. The Tongjian focuses heavily on fiscal policy, military reform, and the relationship between rulers and their ministers because those were the issues that defined the Song political debate. Sima Guang’s selection of historical episodes is not random. It is shaped by the questions that mattered to him and his contemporaries: How should taxes be structured? How should the military be controlled? What happens when a ruler trusts only one faction? When is reform appropriate, and when is it destructive?

Second, the political context explains the Tongjian’s method. Sima Guang’s insistence on chronological narration, his separation of narrative from commentary, and his careful evaluation of sources all reflect a historian who wanted his evidence to be examined rather than simply accepted. He knew that his evaluative comments would be read as political arguments, and he designed the text so that readers could assess those arguments against the factual record. The Tongjian is, in this sense, a deeply democratic work: it invites the reader to disagree with the author by checking the evidence.

Eunuch Power and the Poisoning of Late Tang Governance

One of the most disturbing themes in the Tongjian’s Tang coverage is the rise of eunuch power, which Sima Guang treats as a direct consequence of the institutional failures exposed by the An Lushan Rebellion. Before the rebellion, eunuchs at the Tang court served primarily as palace attendants and trusted messengers. After the rebellion, emperors who could no longer trust their military governors turned to eunuchs as the only power center whose loyalty was personally guaranteed.

The turning point came with the rise of eunuch generals commanding the Shence Armies (神策军, Divine Strategy Armies), the palace guard units that became the most powerful military force in the empire after the rebellion. By the ninth century, eunuch generals controlled these armies and, through them, the physical security of the emperor and the succession itself. Several Tang emperors were installed or deposed by eunuch factions. The Tongjian documents this process with growing alarm, showing how each concession to eunuch power made the next concession easier.

The most infamous episode was the Sweet Dew Incident (甘露之变) of 835 CE, in which Emperor Wenzong attempted to eliminate eunuch power through a palace coup. The plot failed catastrophically when the eunuchs discovered the plan. The military governors the emperor had counted on for support did not arrive in time, and the eunuch commanders of the Shence Armies seized the palace, killed the officials who had supported the plot, and established themselves as the effective rulers of the court. Emperor Wenzong spent the remaining years of his reign as a puppet, reportedly unable even to appoint his own heir.

Sima Guang’s commentary on the Sweet Dew Incident is one of the most agonized passages in the Tongjian. He faults the emperor for the failed execution but directs his sharpest criticism at the decades of policy failure that made the plot necessary. Once eunuch military power was institutionalized, it could not be removed without a force stronger than the eunuchs controlled. The court had voluntarily created a power center that no one could dislodge, and the result was decades of governance by palace clique.

You cannot give someone a sword and then ask for it back. The Tang court gave eunuchs armies, and then found that the armies no longer listened to anyone but the eunuchs. The correction would have been to not give the armies in the first place, but that correction was only visible in retrospect.

The Tang Cultural World Through the Tongjian

Although the Tongjian is primarily a political history, its chronological framework means that cultural developments appear as part of the political narrative rather than in isolated treatises. The rise of Tang poetry, the development of the examination culture, the spread of Buddhism, and the evolution of the civil service all appear in the Tongjian woven into the story of decades rather than summarized in a separate section.

The Tang produced some of the greatest poets in world history: Li Bai (李白, 701 to 762), Du Fu (杜甫, 712 to 770), and Bai Juyi (白居易, 772 to 846), among hundreds of others. The Tongjian mentions these figures when their lives intersect with political events. Li Bai’s brief and disastrous association with the rebel prince Lin during the An Lushan Rebellion is recorded. Du Fu’s difficult years as a minor official during the same rebellion are documented. Bai Juyi’s political career, which included service as a governor and memorials to the throne on policy questions, appears in the narrative of the mid-ninth-century court.

The Tongjian also documents the development of the Buddhist establishment. Tang Buddhism reached extraordinary levels of institutional power and intellectual sophistication. The monk Xuanzang (玄奘, 602 to 664) traveled to India and returned with Buddhist scriptures that would reshape Chinese Buddhism. The translation projects Xuanzang led at the Big Wild Goose Pagoda in Chang’an produced some of the most important texts in East Asian Buddhism. Sima Guang records these developments as part of the political context, noting the resources devoted to Buddhist institutions and the debates at court about the appropriate level of state support for religious establishments.

The most dramatic confrontation between Buddhism and the Tang state was the Great Persecution of 845 CE, when Emperor Wuzong ordered the suppression of Buddhist monasteries, the forced laicization of monks and nuns, and the confiscation of monastic property. The Tongjian documents this event in detail, and Sima Guang’s commentary is revealing. He is not a Buddhist sympathizer, but he sees the persecution as a symptom of the same governance failures he criticizes throughout: instead of addressing the structural problem of monastic wealth accumulation through policy, the emperor chose a sudden, violent solution that created chaos and solved nothing permanently. The Tongjian’s assessment is that gradual fiscal reform dealing with the underlying issues would have been more effective than a dramatic persecution.

The Tongjian’s Legacy: Influence on Chinese Historiography and Beyond

The Zizhi Tongjian was not just a book. It was a methodological revolution that changed how Chinese history was written and read for the next nine hundred years. Its influence can be traced through three channels: the continuation and abridgment tradition, the institutional adoption of chronological history as an official format, and the way it shaped the reading and teaching of history in the examination culture of later dynasties.

Continuations and Abridgments

Sima Guang’s work ended in 959 CE, which meant that the entire Song dynasty and everything after it remained unchronicled in the Tongjian format. This gap was filled by a series of continuations, the most important of which was the Xu Zizhi Tongjian (续资治通鉴, the Continuation of the Comprehensive Mirror), compiled by the Qing dynasty scholar Bi Yuan (毕沅) in the late eighteenth century. Bi Yuan’s continuation covered the Song, Yuan, and Ming dynasties, extending the chronological narrative from 960 to 1644 CE and effectively creating a unified chronological history of imperial China.

Other continuations extended the format further. The Ming dynasty scholar Chen Jiru produced a continuation covering the Song. The Qing dynasty scholar and statesman Zuo Zongtang (no relation to the famous general) produced an abridgment. The most widely read abridged version, however, was the Tongjian Gangmu (通鉴纲目), created by the great Neo-Confucian philosopher Zhu Xi (朱熹, 1130 to 1200). Zhu Xi’s version, which compressed Sima Guang’s text into a more manageable format while preserving its chronological structure and adding his own moral commentary, became the standard version read in schools and studied for the examination system. For most educated Chinese of the Ming and Qing dynasties, their knowledge of the Tongjian came through Zhu Xi’s abridgment rather than through Sima Guang’s original.

The Tongjian Jishi Benmo (通鉴纪事本末) deserves special mention. Compiled by the Yuan dynasty scholar Yuan Shu, this work took the material from the Tongjian and reorganized it by event rather than by year. Where the Tongjian presents events chronologically, jumping between different regions and topics within a single year, the Benmo version collects all the material related to a single event or topic (for example, the An Lushan Rebellion, or the fall of the Western Jin) into a single continuous narrative. This format proved so useful that it became a recognized historical genre in its own right, the jishi benmo (纪事本末) format, which was subsequently applied to other periods of Chinese history.

The Innovation of Chronological History

Before the Tongjian, Chinese history was written primarily in the biographical format established by the Shiji: basic annals for rulers, biographies for individuals, treatises for institutions. This format served a specific purpose: it connected individuals to events and allowed readers to understand a person’s role in history. But it made it extremely difficult to understand the flow of events over time. If you wanted to know what was happening across all of China in the year 350 CE, you had to read the annals of every relevant dynasty, the biographies of every relevant figure, and then mentally reconstruct the sequence.

The Tongjian solved this problem by organizing everything chronologically. The result was a text that read more like a narrative than like a reference work, and that allowed readers to follow the chain of causation across years and decades. Sima Guang’s method was not entirely new. The Chunqiu (春秋, Spring and Autumn Annals) had been chronological, and the竹书纪年 (Bamboo Annals) had attempted a similar chronological record for an earlier period. But no one had attempted a chronological history at this scale before, and Sima Guang’s success in executing it demonstrated that the format was viable for works covering thousands of years.

The Tongjian’s real innovation was not its political philosophy or its moral commentary. It was the demonstration that chronological narrative at scale was possible and useful. That demonstration changed Chinese historiography permanently.

The Tongjian and the Examination Culture

Through Zhu Xi’s abridgment and the examination system, the Tongjian’s approach to history became embedded in the education of every Chinese official from the Song dynasty onward. The examination tested more than knowledge of the classics but the ability to apply historical lessons to contemporary problems. Students were expected to know the major events of the Tongjian and to be able to write essays that drew on its episodes to argue for or against particular policies.

This created a shared historical vocabulary among educated Chinese. When a Ming dynasty minister wanted to warn the emperor against trusting a single advisor, he could reference Emperor Xuanzong’s reliance on Li Linfu before the An Lushan Rebellion. When a Qing dynasty official wanted to argue against rapid institutional reform, he could reference Wang Mang’s reforms and the chaos that followed. These references were immediately understood because every literate official had read the same texts. The Tongjian, more than any other historical work, provided the common stock of historical examples that Chinese political culture used to think about governance.

Modern Reception

In the twentieth century, the Tongjian underwent a complex reevaluation. The May Fourth intellectual movement criticized it as an artifact of feudal political thought, a work written to advise emperors in a world that no longer had emperors. Marxist historians saw it as a Confucian text that obscured class dynamics beneath moral commentary. Yet the Tongjian’s methodology, its commitment to chronological narration and source evaluation, continued to be respected by professional historians, and its narrative remained the single best entry point for understanding the political history of the periods it covers.

Today, the Tongjian occupies a position in Chinese historical consciousness roughly comparable to that of Thucydides in Western historical thought. It is too long for most casual readers, but its abridged versions are widely read. Scholars return to the original for its unmatched density of detail and its careful source criticism. And its central argument, that governance is a learned skill that can be studied through historical evidence, remains relevant in any political system that asks its leaders to learn from the past.

East Asian Reception: The Tongjian in Japan, Korea, and Vietnam

The Tongjian’s influence was not confined to China. Its methodology and its political philosophy spread throughout the East Asian cultural sphere, becoming a foundational text for governance education in Japan, Korea, and Vietnam. The Tongjian arrived in Japan by the late Heian period and was studied intensively by Kamakura and Muromachi shogunate officials who saw in its lessons on military coups and civilian control over armed forces a direct relevance to their own warrior government.

Japanese scholars produced important commentaries and abridgments of the Tongjian. The Shōkōkan, a shogunate historical bureau established in the late eighteenth century, explicitly modeled its compilation practices on Sima Guang’s methods. The Dai Nihonshi (大日本史, History of Great Japan), compiled by the Mito domain across the seventeenth to nineteenth centuries, adopted the biographical format of the Shiji rather than the chronological format of the Tongjian, but the source-critical method employed by the Mito scholars owed a clear debt to Sima Guang’s approach.

In Korea, the Tongjian was a standard text for yangban (aristocratic) education from the early Joseon dynasty. King Sejong, famous for commissioning the Korean alphabet, reportedly studied the Tongjian with his advisors and used its case studies to frame policy discussions. The Korean civil examination system, modeled on the Chinese keju, included questions based on Tongjian episodes. The text’s focus on the dangers of factional conflict resonated deeply in a Korean political culture that was itself defined by intense factional struggles throughout the Joseon period.

The Tongjian’s Foresight on Climate and Demographic Disasters

Modern readers may overlook the Tongjian’s treatment of environmental and demographic crises, but Sima Guang documented them extensively and drew political lessons that remain relevant. The text records droughts, floods, famines, and locust plagues with consistent attention, noting where government response was effective and where it failed.

The most severe environmental crisis the Tongjian documents is the series of droughts that devastated north China in the late ninth century, roughly coinciding with the Huang Chao Rebellion. Sima Guang shows that these droughts were not the primary cause of the rebellion, but they created the conditions of mass displacement and economic desperation that made rebellion possible. His analysis of the linkage between environmental stress and political instability is one of the precursors to modern environmental security studies, even though it is presented in the language of eleventh-century Confucian political thought.

Why the Tongjian Has No True Western Equivalent

The scale and ambition of the Tongjian make it difficult to compare with any single Western historical work. Thucydides, the closest Western parallel in terms of methodological sophistication, covered a single war lasting twenty-seven years. The Tongjian covers 1,362 years. Edward Gibbon’s Decline and Fall of the Roman Empire covers roughly thirteen centuries, but Gibbon wrote as a single author over twenty years, while the Tongjian was produced by a team led by a working politician, and it covers a far more complex political landscape involving dozens of dynasties and states.

The closest Western parallel to the Tongjian’s function in its own culture is not a single historical work but the accumulated corpus of political philosophy and statecraft literature that runs from Aristotle through Machiavelli to the Federalist Papers. The Tongjian serves the same function in Chinese political culture: it provides the case studies, the arguments, and the historical vocabulary that political actors use to think about governance. The difference is that the Tongjian compiled all of this in a single chronological narrative, whereas the Western tradition distributed it across many separate texts.

This helps explain why the Tongjian is so difficult to translate into English and why it remains relatively unknown outside East Asian studies. It is not just long. It is deeply embedded in a political culture that does not map neatly onto Western categories. The institutions it describes, the political concepts it deploys, and the moral framework within which it evaluates governance all require explanation that, if done properly, would make the text several times longer than it already is.

Reading the Tongjian Today: Translations, Approaches, and Modern Relevance

The Zizhi Tongjian is a massive text, roughly three million Chinese characters across 294 chapters, and no complete English translation exists. This is not a failing of Western sinology. It is a reflection of the text’s scale and the difficulty of translating a narrative that assumes a deep familiarity with Chinese history, geography, and political institutions. For readers who want to engage with the Tongjian today, the question is what to read and how to approach it.

Chinese Editions and Abridgments

The most accessible Chinese edition for general readers is the Zhonghua Book Company (中华书局) annotated edition, published in twenty volumes with modern punctuation and occasional annotations. This edition, first published in 1956 and revised several times since, is the standard scholarly text. The annotations clarify geographic names, official titles, and dates that would otherwise be opaque to modern readers.

For readers who want a shorter version, Zhu Xi’s Tongjian Gangmu remains the most influential abridgment, though it reflects Zhu Xi’s Neo-Confucian editorial choices and should not be treated as a neutral representation of Sima Guang’s text. Several modern abridgments exist, with the most popular being the Zizhi Tongjian Xuan (资治通鉴选), which selects the most famous episodes and provides modern Chinese commentary.

The Tongjian vs the Shiji: Two Models of History

For anyone interested in Chinese historical writing, the comparison between the Tongjian and the Shiji is essential. They are the two greatest works of Chinese history, and they represent fundamentally different approaches to the historian’s task.

The Shiji, written by Sima Qian in the early first century BCE, organizes history by genre: basic annals for rulers, hereditary houses for feudal lords, biographies for individuals, treatises for institutions, and chronological tables. This structure allows the reader to understand individuals in depth, to see how a person’s character and decisions shaped events. But it makes it difficult to follow the sequence of events chronologically, because the same event may be narrated differently in the annals, in a biography, and in a treatise.

The Tongjian, written eleven hundred years later, organizes everything by year. This structure makes it easy to follow the chain of causation across time but sacrifices the individual depth that the Shiji’s biographical format provides. Sima Guang’s evaluative comments (臣光曰) serve some of the same function as Sima Qian’s biographical introductions and concluding assessments, but they are shorter and more focused on political lessons than on personal character.

The two works also differ in scope and purpose. The Shiji covers from the legendary Yellow Emperor through Sima Qian’s own time, encompassing both myth and history. The Tongjian covers a more restricted but better-documented period, from 403 BCE to 959 CE, and explicitly excludes mythological material. The Shiji was written by a man who had suffered castration for defending a defeated general and who wrote, in part, to vindicate his own understanding of honor and justice. The Tongjian was written by a senior official who wanted to provide his emperor with a practical tool for governance. The personal intensity of the Shiji contrasts with the bureaucratic precision of the Tongjian, and both qualities have their value.

Read the Shiji to understand people. Read the Tongjian to understand systems. Together they give you what neither can alone: the individual and the structure, the character and the institution, the story and the pattern.

Why a Thousand-Year-Old History Book Still Matters

It is reasonable to ask why a text written to advise Song dynasty emperors should be relevant in the twenty-first century. The answer is that the Tongjian’s subject matter, the relationship between political decisions and their consequences, is not specific to imperial China. Every political system faces versions of the same questions that Sima Guang addresses: How should leaders balance advice from different factions? When is reform appropriate and when is it destructive? How do you maintain military capability without letting military power undermine civilian government? What happens when a leader stops listening to unwelcome information?

These questions do not have timeless answers. They have context-dependent answers, and the value of the Tongjian is that it provides 1,362 years of context. When a modern manager is tempted to surround themselves with people who agree with them, the Tongjian’s account of Emperor Xuanzong and Li Linfu is a warning. When a modern organization is considering sweeping structural reform, the Tongjian’s account of Wang Mang and Emperor Xiaowen provides cautionary tales. The specifics are different, but the pattern, which is what Sima Guang wanted his readers to see, repeats.

The Tongjian and Chinese Strategic Culture

For anyone interested in Chinese strategic thought, the Tongjian is an essential complement to the better-known military classics like the Sunzi Bingfa (孙子兵法). Where the Sunzi discusses strategy in the abstract, the Tongjian shows strategy in practice: how alliances form and break, how intelligence failures lead to disaster, how logistics determine outcomes, how political divisions within a state create military vulnerabilities. For readers of Chinese literature and philosophy, the Tongjian provides the historical context that gives meaning to the theoretical texts. The Han Feizi’s theories of legalist governance come alive when you see them applied (and misapplied) by rulers in the Tongjian. The Confucian emphasis on ministerial remonstrance becomes concrete when you read Sima Guang’s accounts of ministers who spoke truth to power and paid the price, and rulers who listened and prospered, or did not listen and fell.

Frequently Asked Questions

How long does it take to read the Zizhi Tongjian?

Reading the full 294-chapter text at a moderate pace takes approximately 200 to 300 hours. Most modern Chinese readers start with selected chapters or an abridgment. The Tang dynasty section (roughly chapters 185 to 270) is the most popular starting point because it contains the most dramatic narrative arc and covers the most influential period.

Is there a complete English translation?

No. Several English-language studies of the Tongjian exist, and portions have been translated in academic articles and textbooks, but the full text is too long and too culturally embedded for a practical complete English edition to have been produced. The most accessible English-language introduction to the Tongjian’s method and content is the scholarly work of Ji Xiaofu and others, which provides annotated translations of key passages.

What is the difference between the Tongjian and the Shiji?

The Shiji (Records of the Grand Historian, compiled circa 100 BCE) is organized by genre (annals, biographies, treatises), while the Tongjian (compiled 1065 to 1084 CE) is organized purely by year. The Shiji covers from legendary antiquity to the early Western Han. The Tongjian covers 403 BCE to 959 CE. The Shiji is more literary and personal, the Tongjian more systematic and politically focused. Both are essential, and they cover overlapping periods from different angles.

What is the “minister Guang says” (臣光曰) commentary?

These are Sima Guang’s own evaluative comments, placed after significant episodes in the narrative. They offer moral and political judgments on the events just described. There are over 300 such comments in the text, and they constitute one of the most sustained works of political philosophy in the Chinese tradition. They are also the primary lens through which Sima Guang makes his argument about governance.

Why did Sima Guang start in 403 BCE instead of earlier?

Sima Guang believed that the division of the state of Jin in 403 BCE marked the beginning of the Warring States period, when political governance became systematic enough to be studied as a continuous story. Earlier periods, in his view, were too mythologized or too sparsely documented to serve as a reliable mirror for rulers. This is a methodological choice, not a judgment about what was historically important.

Is the Tongjian politically biased?

Yes, in the sense that Sima Guang had clear political views (conservative, anti-reform, pro-stability) that shaped his selection and evaluation of events. But the Tongjian is designed to let readers evaluate his biases against the evidence. The narrative is factually careful, the sources are cited, and the commentary is clearly separated from the narration. A reader who disagrees with Sima Guang’s evaluative comments can still use the narrative as a reliable historical record.

The Tongjian’s Lessons for Modern Organizations

While the Tongjian was written for emperors, its lessons translate into modern organizational life with surprising precision. The text’s core concern is the relationship between leaders and the information they receive, and that relationship is, if anything, more relevant in modern organizations than it was in eleventh-century Chinese courts. Today’s leaders face the same fundamental challenge Sima Guang identified: the people closest to a decision-maker often have incentives to present information that confirms existing beliefs and to suppress information that contradicts them.

The Tongjian’s antidote is institutional: create structures that require critical advice, protect dissenting voices, and separate the reporting of facts from the interpretation of those facts. Sima Guang’s separation of narrative and commentary is not just a literary technique. It is an organizational design principle: keep the raw data and the evaluative judgment in separate channels, so that readers can assess the judgment against the evidence rather than having to take the author’s word for both.

How to Study the Tongjian: A Practical Guide for Non-Specialists

For readers approaching the Tongjian without specialist training in Chinese history, the text can feel overwhelming. Here is a practical approach that has been used by generations of Chinese students and that remains the most effective way to engage with the work.

Start with the Tang dynasty section. The Tang is the most extensively documented period in the Tongjian, covering roughly one-third of the entire text. The narrative arc of the Tang, from brilliant founding through golden age to catastrophic rebellion and slow decline, provides a clear structure that helps readers navigate the detail. Begin with the founding and the Zhenguan era (chapters 185 to 195) and read through the An Lushan Rebellion (chapters 217 to 222). This gives you the high point and the turning point in one continuous sequence.

After completing the Tang core, move to the comparison sections. Read the Tongjian’s account of the Sui alongside that of the Tang founding. The Sui-Tang transition is one of the most carefully narrated sections, and Sima Guang’s clear intent to show how the Tang learned from the Sui’s mistakes makes the lessons explicit. Then read the Five Dynasties section for a contrast: what happens when institutional learning fails.

The Tongjian’s Place in World Historiography

The Tongjian deserves a place in any survey of world historiography alongside Thucydides’ History of the Peloponnesian War, al-Tabari’s History of Prophets and Kings, and Gibbon’s Decline and Fall. What makes it comparable to these world-class works is not its length or its comprehensive scope but its commitment to a methodological principle: that the historian’s job is to trace causation through evidence, to separate fact from evaluation, and to let the reader reach their own conclusions.

Sima Guang did not invent this principle. He inherited it from the Chinese historiographical tradition that began with Confucius’s editing of the Chunqiu and ran through Sima Qian’s Shiji. What Sima Guang did was apply the principle at a scale no previous historian had attempted. When he finished, the result was the most comprehensive, most carefully sourced, and most critically self-aware historical work produced in any civilization before the modern era.

The Tongjian’s Continuing vitality comes from its understanding that governance is a learned skill that can be studied through historical evidence, and that the evidence, if honestly compiled and clearly presented, will teach lessons that no theory can provide. In an era where decision-makers have more data than ever before but less clarity about what it means, the Tongjian’s method, distinguish evidence from interpretation, trace causation through events, and let the evidence challenge assumptions, remains as necessary as it was in Sima Guang’s time.

The Tongjian was written to save the Song dynasty. When you spend nineteen years analyzing 1,300 years of governance, youveau realize that the question is never what to do, but whether you can see clearly enough to know what actually needs doing. The mirror’s purpose is not to tell you what to think. It is to show you what is there.

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