Emperor Taizong of Tang

Li Shimin, who reigned from 626 to 649 under the temple name Taizong, is the ruler most often held up in Chinese political writing as the model of what an emperor ought to be. The phrase Zhenguan zhi zhi — the good government of the Zhenguan era, after his reign title — became a yardstick against which later administrations were measured, quoted by reformers in the eleventh century, by officials of the Ming, and by statesmen of the twentieth.
That reputation rests on twenty-three years of deliberate statecraft: a rebuilt bureaucracy, a revised legal code, a lighter tax burden, and a foreign policy that extended Tang authority from the Korean peninsula to the oasis cities of Central Asia. It rests equally on something harder to institutionalise — a court culture in which the emperor was expected to be told, in public and at length, that he was wrong.
The reputation also has a fault line running through it. Li Shimin took the throne by killing two of his brothers on a single morning, and he never entirely escaped the consequences of that day.

1. A Prince of the Sui (598 – 617)

Li Shimin was born on 28 January 598 at the Li family's estate at Wugong, in what is now Shaanxi province. The Old Book of Tang, the official history compiled a century later, gives 599 instead, and the discrepancy has never been fully settled, though 598 is the date generally used. His father, Li Yuan, was a Sui official of aristocratic Sino-Xianbei descent and a cousin of the reigning imperial house.
His mother, Lady Dou, came from a family that had married into the Northern Zhou imperial clan. Li Shimin was their second legitimate son. The couple had four sons and one daughter: Li Jiancheng, the eldest; Princess Pingyang, who would one day raise an army in her father's cause; Li Shimin himself; Li Xuanba, who died young; and Li Yuanji, the youngest.
Family tradition, as the official historians recorded it, held that a fortune-teller had examined the infant and pronounced that he would one day "bring order to the world and peace to the people" — the literal sense of the name Shimin. The anecdote may well be retrospective embroidery of the kind that attaches to founders.
What can be said with more confidence is that Li Yuan educated his sons on both sides of the classical curriculum: the Classic of Filial Piety and the Analects first, then the Five Classics and the literary anthology Wenxuan, alongside calligraphy, horsemanship and archery. Li Yuan had won his own wife in an archery contest, and martial skill was not treated as an optional extra for boys who might one day have to command troops.
Two events of his adolescence shaped the man. In 613, when he was about fifteen, his mother died at Zhuojun in the far north-east. Her kinsman Gao Shilian, casting about for a match for his niece, settled on the young Li Shimin; the girl he married — known to history as Empress Zhangsun — would be his closest political partner for the next twenty-three years. Then in 615 the emperor Yang of Sui was surrounded by Eastern Turkic cavalry at Yanmen.
A sixteen-year-old Li Shimin answered the call for volunteers and, according to the Old Book of Tang, advised his commanding general to feign overwhelming numbers by stretching banners across the hills by day and beating war drums by night. The Turks withdrew. It is the first recorded instance of an instinct that ran through his entire career: when you are weaker, look as though you are stronger.

1. The Soldier Prince (617 – 626)

In 617 Li Yuan rose in rebellion at Taiyuan, and his second son became the campaign's most effective field commander. Between 618, when the Tang was proclaimed at Chang'an, and 628, when the last serious rival was broken, Li Shimin fought a succession of engagements that secured the new dynasty's grip on the north China plain, defeating in turn Xue Rengao, Liu Wuzhou, Wang Shichong and Dou Jiande.
The decisive operation came in 621 at Hulao Pass. Li Shimin had Wang Shichong besieged inside Luoyang; Dou Jiande marched down from Hebei with a large army to relieve him. Rather than lift the siege, Li Shimin divided his forces, left a holding detachment before Luoyang, and met Dou Jiande in the open with cavalry he had spent weeks drilling while the siege stalled. Dou Jiande was captured, his army disintegrated, and Wang Shichong surrendered soon afterwards.
The two strongest surviving states of the north were destroyed in a single campaign. It was on the strength of victories like this that Li Shimin was created Prince of Qin and given a personal staff of advisors who later formed the core of his government.
Military success also made him a problem. Li Jiancheng was crown prince; Li Yuan's court split into a faction around the heir and a faction around the general who had actually won the war; and the rivalry sharpened as Li Shimin's followers accumulated offices and titles. By the mid-620s both sides were openly manoeuvring for position. Li Shimin moved first.

1. Xuanwu Gate and the Crisis of 626

Shortly after dawn on 2 July 626, at the Xuanwu Gate of the palace complex in Chang'an, Li Shimin and a small party of horsemen ambushed the crown prince Li Jiancheng and his brother Li Yuanji, killing both. Their sons were executed soon after. Three days later Li Shimin was appointed crown prince; in early September Li Yuan abdicated; and the following spring the reign title was changed to Zhenguan. Li Shimin was twenty-seven.
The event is the point on which most later argument about Taizong turns. The official histories were compiled under his own patronage, and it is plain that the record was shaped to present Li Jiancheng and Li Yuanji as scheming incompetents who had it coming. Historians have argued over how much of the account is invention and how much reflects a genuine death-struggle between two irreconcilable factions; the honest answer is that we cannot know.
What is not in dispute is that the first emperor of the Tang's second generation reached the throne as a fratricide, and that he governed for the rest of his life with the knowledge that this was the first thing anyone would ever say about him.
He had no time to dwell on it, because the dynasty nearly fell within weeks. The Eastern Turkic qaghan, Illig, had taken advantage of the Sui collapse to push south, and in the autumn of 626 his cavalry crossed the Yellow River and appeared in force on the Wei River outside Chang'an — with, by the traditional account, a hundred thousand horsemen. Most of the Tang field army was far away.
Taizong rode out from the city with a small escort, met the qaghan at the Bian Bridge, and talked him into withdrawing, reportedly by a combination of visible self-assurance and a substantial payment. The episode — the Oath of the Wei River — was recorded as a humiliation.
It also set the direction of Tang foreign policy for the next four years: no rash wars, a steady build-up of cavalry, and patient exploitation of the fault lines inside the Turkic confederation.

1. Governing the Realm: the Zhenguan Reforms

Taizong's administrative achievement is easier to describe than to dramatise, and it is the foundation of his reputation. At the centre of it stood the Three Departments and Six Ministries: the Zhongshu, which drafted policy; the Menxia, which had the right to reject or send it back; and the Shangshu, which executed it through six functional ministries.
In practice the machinery worked because of the Council of State, where senior officials argued out policy before it became edict, and because Taizong allowed men with no family connection to him to sit in it.
The most famous member of that circle was Wei Zheng, a former advisor to one of Li Shimin's defeated enemies who became the court's professional dissenter. He submitted memorials criticising the emperor's conduct, his building projects, his hunting expeditions and his temper, and he did so repeatedly and in writing.
Other senior figures — Fang Xuanling and Du Ruhui, whose complementary talents produced the proverb "Fang plans, Du decides"; the general Li Jing; the Empress's brother Zhangsun Wuji — filled out what became known as the Zhenguan court. The point was not that Taizong was uniquely virtuous. The point was that he had constructed a working expectation that disagreement was survivable, which is rarer in any political system and was almost unknown in imperial China.
In law, the Zhenguan Code of 637 revised and moderated the harsh Sui statutes: penalties were graded more carefully, some categories of mutilation were dropped, and the review of death sentences was tightened so that capital cases were argued through the emperor three times, and in some categories five.
The Comprehensive Mirror in Aid of Governance, compiled centuries later, records that in 630 only twenty-nine people were executed throughout the empire — a figure that should be treated as a traditional claim rather than a statistic, but one that later ages repeated because they wanted it to be true.
In economic life the state worked through the equal-field system, under which land was periodically redistributed according to household size, and the tax regime known as zu yong diao — a levy in grain, a levy in cloth, and a fixed number of days of labour. Military service ran through the fubing militia: soldier-farmers who rotated between their fields and their units, which kept the standing army small and cheap.
Taizong's government also reopened and expanded the schools, enlarged recruitment through examination, commissioned the orthodox commentaries on the Five Classics completed under Kong Yingda in 640, and established a palace history bureau that produced the official histories of the Liang, Chen, Northern Qi, Zhou and Sui dynasties in 636, followed by the Book of Jin in 646.
He also, at least in the first half of his reign, spent conspicuously little: construction was curtailed, the Sui's more extravagant palaces were left closed, and the palace establishment was pruned.

1. The Heavenly Khan: the Steppe and the West

The Oath of the Wei River was answered in 630. Taking advantage of a succession dispute and a hard winter among the Eastern Turks, Taizong sent Li Jing north with a cavalry force that made a night march over the Yin Mountains and surprised the qaghan's camp. Illig was captured and brought to Chang'an.
Taizong declined to have him executed, gave him a title and a residence, and kept him at court — a piece of political theatre that told every Turkic nobleman watching that surrender was survivable and even profitable. The Eastern Turkic Khaganate, the dominant power on the northern frontier for decades, ceased to exist.
In the same year the leaders of the Tiele tribes and the kings of the Western Regions conferred on him the title Heavenly Khan (Tian Kehan). The significance is easy to miss. It was a steppe title, offered in the political idiom of the nomads rather than the language of the Chinese Son of Heaven, and by accepting it Taizong claimed a dual legitimacy — emperor of China and overlord of the steppe — that no predecessor had held.
He also settled large numbers of Turkic refugees inside the frontier over the objections of officials who warned that they would eventually turn; in the event, Turkic and Central Asian generals became a standing feature of Tang armies.
Westward, the pattern was a mixture of marriage and garrisons. In 635 Li Jing broke the Tuyuhun in the Qinghai region. Relations with the new Tibetan empire under Songtsen Gampo began badly: a marriage request was refused in 636, Tibet raided the frontier in 638, and Tang forces pushed them back.
A second request in 640 was granted, and in 641 the Princess Wencheng travelled to Tibet as the qaghan's bride — traditionally credited with carrying silk, grain-milling techniques and medicine, and with the arrival of Buddhism at the Tibetan court, though Buddhism was already known there.
In 639–640 a campaign under Hou Junji destroyed the kingdom of Gaochang, which had been blocking the trade route and had allied with the Western Turks; its territory became the prefecture of Xizhou, and in September 640 the Anxi Protectorate was established at Jiaohé to supervise the region. Karasahr was brought to heel in 644 and Kucha in 648, and the four garrison towns of Kucha, Karasahr, Khotan and Kashgar — the Anxi Four Garrisons — took shape.
In 646 the Tang, working with the Uyghurs and other Tiele tribes, destroyed the Xueyantuo khaganate and divided its territory into six commands and seven prefectures; the Yanran Protectorate followed in 647.
The consequence was not merely military. With the eastern half of the Silk Road under firm control, Chang'an became one of the most cosmopolitan cities on earth. Sogdian merchants ran the caravan trade; in 635 a Christian missionary named Alopen arrived from Persia and was permitted to establish what became the Nestorian church of China, commemorated six generations later on the Xi'an Stele; Manichaean and Zoroastrian communities followed.
In 629 a monk named Xuanzang had left the empire illegally to travel to India in search of Buddhist texts. He returned in January 645 to a hero's reception, was received by the emperor, and was given state support for a translation project that would occupy him for the rest of his life.
His account of the journey, the Great Tang Records on the Western Regions, remains one of the most important sources for the history and geography of medieval Central Asia — and it exists because Taizong was interested in what lay beyond his frontier.

1. Family: an Empress, Fourteen Sons, Twenty-One Daughters

Empress Zhangsun died in 636 at the age of thirty-five. She had been careful, in twenty-three years of marriage, about the boundary between consort and minister: she advised her husband privately, argued for clemency, and resisted the promotion of her own relatives. Her brother Zhangsun Wuji nonetheless became one of the most powerful men at court, and after her death Taizong built a terrace from which he could look toward the mountain where she was buried.
Her death was the first in a sequence of losses that turned his last decade into a study in family failure.
He had fourteen sons and twenty-one daughters by his empress, his consorts and his concubines. The heir apparent, Li Chengqian, was named crown prince on his father's accession. He grew up capable but erratic, and his position was undermined by his own younger brother Li Tai, a brilliant and favoured prince who cultivated his own following at court and let it be known that he expected the succession.
In 643 the crown prince was implicated in a conspiracy with, among others, the general Hou Junji — the conqueror of Gaochang — to seize power by force. The plot was uncovered; Li Chengqian was deposed and exiled, dying two years later; Li Tai, whose manoeuvring was obvious to everyone, was packed off to a provincial post and barred from the succession.
An account in the Comprehensive Mirror has Taizong, in despair at his sons' behaviour, threatening to kill himself with a knife before officials restrained him, and then naming his ninth son, Li Zhi, as the new crown prince. Whatever the literal truth of that scene, the decision was real: in 643 Li Zhi, then fifteen, was made heir, and he duly succeeded in 649 as Emperor Gaozong.
Five years earlier, in 637, a fourteen-year-old girl had entered the palace as a fifth-rank concubine with the name Wu Mei. She would outlast almost everyone connected with this story: recalled from a convent by Gaozong, she became empress in 655 and eventually ruled China in her own name as the only woman in its history to do so.
The same year that cost him his heir also cost him Wei Zheng, who died in 643. Taizong's celebrated remark on the occasion — that a man needs a bronze mirror for his appearance, history for the rise and fall of states, and an honest colleague to show him his own mistakes, and that he had now lost that last mirror — is quoted in every Chinese discussion of the ideal ruler. The sequel is less often quoted.
Learning that Wei Zheng had shown copies of his remonstrances to the court historian, Taizong flew into a rage, revoked the marriage he had arranged between his daughter and Wei Zheng's son, and ordered the stele he had erected over Wei Zheng's grave destroyed. The man who wanted an honest mirror did not always want to look into it.

1. Korea, and the Last Years

In 642 the Goguryeo general Yeon Gaesomun murdered his king and installed a puppet, then allied with Baekje against Silla, a Tang client state. Taizong decided on war, over the objections of several senior advisors. In 644 he left for the front in person with a large army. The 645 campaign went well in the field: Tang forces took a string of Liaodong cities, and Taizong's personal command of the cavalry won engagements against numerically superior opponents.
But the advance stalled at Anshi Fortress, where a determined defence held the Tang army for months. Winter came, supplies ran short, and Taizong withdrew — a withdrawal presented at court as a victory and understood by everyone as something else. Further, smaller expeditions followed in 647 and 648; a major invasion was planned for 649, and was cancelled when the emperor died.
The Korean campaigns are the clearest instance of the costs of his later reign: conscription on a large scale, heavier taxes to pay for it, and the small-scale unrest that the histories record in the provinces. The remonstrance that had defined his early court grew thinner as the men who supplied it died or fell out of favour — Wei Zheng in 643, Fang Xuanling in 648.
He had also become preoccupied with his own mortality, and in 648 accepted a longevity drug from an Indian alchemist, which worsened his health rather than restoring it. In 648, conscious of his situation, he wrote the Model for an Emperor, a manual of instruction for Li Zhi. It is frank about its author's shortcomings in a way few imperial testaments are.

1. Death, Burial, and Legacy

Taizong died at the Cuiwei Palace in the Zhongnan Mountains, south of Chang'an, on 10 July 649, at the age of fifty by Western reckoning and after twenty-three years on the throne.
He was buried in the Zhao Mausoleum in the Jiuzong range, and the tomb complex was decorated with reliefs of the six horses that had carried him through his campaigns — four of them are now in the Beilin Museum in Xi'an, and two, cut out and sold abroad in 1914, are in the University of Pennsylvania Museum. He was given the temple name Taizong and a posthumous title that was lengthened by later generations.
The image that outlived him was manufactured, in part, by a book he did not write. In the early eighth century an official named Wu Jing assembled a collection of Taizong's conversations with his ministers on the subject of government and called it the Essentials of Government of the Zhenguan Era.
It became a standard text for later Chinese rulers and for courts in Korea, Japan and Vietnam, and it is largely through it that foreign and Chinese readers alike learned what the Zhenguan era was supposed to have been. The irony is structural: a ruler remembered for being scrutinised by his officials is known to us through a book of his own good advice, chosen by an editor.
A balanced verdict has to hold several things at once. Taizong's seizure of power was a brutal coup, covered afterwards by an official history he sponsored. His frontier policy rested on garrisons and campaigns paid for by ordinary households, and his Korean war was a costly failure. He lost one heir to conspiracy and another to ambition.
Yet he also built an administrative machine durable enough to survive his successors' incompetence, a legal code that shaped East Asian law for centuries, and a working expectation of counsel that gave later generations a vocabulary for criticising power. What makes him a durable symbol is not that he was virtuous. It is that he treated being contradicted as part of the job — and, the record suggests, kept failing at it and going back to it anyway.