The Tang Dynasty (618–907 CE) is generally regarded as a golden age in imperial Chinese history. The dynasty’s greatness owes much to its second emperor, Taizong, who helped his father, Gaozu, consolidate the new dynasty and led new conquests to the north and west. A brilliant general and a skillful administrator, Taizong served as an example for his own officials and future emperors, who were equally at home on the field of battle and behind a bureaucrat’s desk.
A Royal Coup
At dawn on July 2, 626 CE, a small group of armed men approached the Xuanwu Gate in northern Chang’an (modern-day Xi’an), the capital of the fledgling Tang Dynasty in China. They were led by Li Shimin, the second son of Gaozu, the founding Tang emperor. For several years, a rivalry had been developing between Shimin and his elder brother and heir apparent, Li Jiancheng, who was supported by their younger brother, Li Yuanji.
Earlier in the year, Yuanji was appointed to lead a campaign against the Eastern Tujue (Turks), and he summoned Shimin’s best generals and troops to join his camp. When Shimin received intelligence that his brothers intended to assassinate him while he was seeing Yuanji off, he recalled his closest advisors, Feng Xuanliang and Du Ruhui, who left Yuanji’s camp disguised as Daoist priests.
Shimin soon sprang into action by falsely accusing his two brothers of illicit relations with the emperor’s concubines, prompting Gaozu to summon his sons to the palace. Shimin led a band of loyal officers to the Xuanwu Gate, which led to the palace complex. Shimin had bribed the gate’s commander, Chang He, his former subordinate, and the latter joined the coup.
As Jiancheng and Yuanji approached the gate, Shimin’s party attacked. Shimin himself shot his elder brother with an arrow, while Yuanji was felled by Shimin’s officer Yuchi Jingde. The latter went to the emperor and informed him of what had just happened. Within a few months, Shimin forced his father to abdicate and mounted the imperial throne.
The Young Rebel
When Li Shimin was born around 600 CE, there was no expectation that he would become emperor. His father, Li Yuan, Duke of Tang, was a military officer who served the Sui dynasty. The Sui was founded in 581 CE by Yang Jian, Emperor Wen of Sui, a talented military leader who was in the process of reunifying China after almost three centuries of division between the Northern and Southern dynasties.
Emperor Wen died in 604 CE and was succeeded by his son, the Emperor Yang. Although the new emperor had been a successful military leader and began several construction projects to develop the Chinese economy, a couple of expensive and unsuccessful campaigns in Korea during the 610s encouraged opposition to the emperor.
The Li family was closely connected to the Sui imperial family, and Li Yuan’s wife, Lady Dou, was the sister of Emperor Yang’s empress. Despite his exalted position at court, Li Yuan had reason to feel insecure when, in 615, the emperor began purging officials named Li in response to a prophecy that the next emperor’s surname would be Li.
According to the official Tang history, the 17-year-old Li Shimin was responsible for encouraging his father to rebel in 617 by presenting him with women from the imperial harem without informing him of their origin. Having inadvertently committed a capital crime, a reluctant Li Yuan had no choice but to lead a rebellion. However, the official history is based on records from Tang Taizong’s reign, which has a tendency to elevate Shimin’s role at the expense of his father.
Reuniting the Empire
Operating from his base at Taiyuan in northern China, Li Yuan and his two eldest sons marched on the Sui capital of Chang’an and laid siege to the city. In late 617, Tang forces breached the walls, and Li Yuan deposed Emperor Yang and made one of his grandsons a puppet emperor. The following summer, he took the throne himself and proclaimed the foundation of the Tang dynasty. After naming Jiancheng as his heir apparent, the new emperor made Shimin Prince of Qin and appointed him to the head of the imperial administration.
Although Gaozu had deposed the Sui emperors and controlled Chang’an, the Tang was one of several new regimes that laid claim to China. In 618, Shimin was dispatched to confront an invasion from the west led by Xue Ju, who had proclaimed himself Emperor of Qin the previous year. Although Shimin was initially defeated, Xue died while marching on Chang’an and was succeeded by his son Xue Rengao. Shimin counterattacked and defeated Rengao, and the latter’s army collapsed and defected en masse to the Tang forces.
The following year, a rebel army led by Liu Wuzhou invaded from the north and briefly captured the Tang heartland of Taiyuan from Li Yuanji. Shimin marched north but avoided battle with the enemy. When Liu’s men ran out of food and were obliged to withdraw, Shimin went on the offensive and routed the enemy.
The Tang empire faced its greatest challenge in the east from the Sui general Wang Shichong, who controlled the eastern capital of Luoyang. In the summer of 620, Shimin marched on Luoyang and gradually occupied much of its hinterland. By the end of the year, Wang requested assistance from fellow rebel Dou Jiande, whose power base was in Hebei and Shandong in the east.
As Dou approached Luoyang in spring 621, Shimin rejected his father’s order to abandon the siege and instead marched the bulk of his army to meet Dou at the Hulao Pass, a strategic fortress that protected the eastern approaches to Luoyang. Shimin captured Dou during the ensuing battle and brought him back to Luoyang as his prisoner. The sight of his ally in chains convinced Wang to surrender, and Shimin gained control of China’s second most important city. The conquest of Luoyang ensured Tang’s ultimate triumph, and most of the rebels were eliminated by 624.
Eastern Turks
Within a few months of becoming emperor, Taizong faced an invasion by an Eastern Turk army led by Illig Qaghan and his nephew, Tolis Qaghan. The Eastern Turks were a formidable power in the northern steppe, and before taking up arms against the Sui, Gaozu had chosen to pay them off with tribute to secure his rear.
In 626, the Eastern Turks had arrived within 100 kilometers of Chang’an when Taizong led his army to meet them at the Wei River. While the traditional histories claim that Taizong defeated the Turks in battle, in reality, he accepted a proposal by his general and advisor Li Jing to pay the Turks a large bribe to make them leave.
Within a couple of years, the balance of power shifted as several Turkic vassals rebelled against their overlords, and the two qaghans (khagans) fell out with each other. In 628 CE, Tolis Qaghan requested an alliance from Taizong against his uncle, but the Tang emperor preferred to sit back and let the Turks destroy each other. In 629, Taizong recognized a rival qaghan who paid tribute to Chang’an, and later that year, Illig Qaghan was also compelled to submit.
The confident Taizong chose to ignore Illig Qaghan’s submission and ordered his generals Li Jing and Li Shiji to invade the Eastern Turkic Qaghanate (or Eastern Turkic Khaganate). By early 630, the Tang armies caught up with the qaghan and took him prisoner. Later that year, a Turkic delegation arrived in Chang’an and acknowledged Taizong as the heavenly qaghan.
Political Reformer
In addition to his military exploits, Taizong gained a reputation for being an ideal ruler. He worked long hours and had his officials post petitions on the walls of his bedchamber so he could consider them at night. He sought and accepted advice and criticism from his officials and ministers, and after becoming emperor, he reduced corvée labor demands by scaling back public works projects. He believed his father’s laws were too strict and revised the law code on a more lenient basis.
Taizong reformed state administration by reducing the number of bureaucratic posts and elevating the status of provincial governorships. Later in his reign, he attempted to recreate a feudal aristocracy by having members of the imperial family or prominent officials holding hereditary posts on the frontiers, but the policy was never implemented in full and was later abandoned.
Throughout his reign, Taizong was supported by a group of talented ministers and officials. Like the emperor, the aforementioned Li Jing and Li Shiji were brilliant leaders on the battlefield and capable ministers in the capital. In addition to leading the campaign against the Eastern Turks, Li Jing served as one of Taizong’s chief ministers between 630 and 634. His younger colleague Li Shiji defended the northern frontier for much of the 630s, and Taizong once remarked that Li Shiji was more effective than the Great Wall in protecting the empire from the Turks. In 643, Li Shiji became a chief minister, but continued to lead campaigns in both the East and West.
Western Campaigns
The Tang conquest of the Eastern Turkic Qaghanate enabled Taizong to control much of what is now Mongolia. During the 630s, he began to turn his attention to the West. During the early years of the Tang, Gaozu had enjoyed good relations with the Western Turks, who ruled over a vast empire in Central Asia and were more concerned about the Persians to their west.
By the 630s, the Western Turkic Qaghanate (or Western Turkic Khaganate) had split into rival eastern and western confederations, and Taizong took advantage of this to force the Western Turkic vassals in the Tarim basin to submit to the Tang. In 641, Taizong fueled the civil war by supporting the claims of Isbara Yabghu Qaghan, the leader of the western confederation, who challenged the claims of his eastern rival Tulu Qaghan, the fugitive son of Illig Qaghan of the Eastern Turks.
When Isbara Yabghu was assassinated by Tulu in 642, Taizong recognized another of Tulu’s rivals who formally surrendered suzerainty over the Tarim basin. By the end of Taizong’s reign in 649, all of the Tarim basin was under Tang control, and his son and successor, Gaozong, was able to conquer the Western Turks in 657.
Final Years
Taizong’s foreign policy was motivated by the desire to recover territories that had once belonged to the Han Dynasty. This included the Korean peninsula, which was divided into Koguryo, Silla, and Baekje kingdoms. The last Sui emperor, Yangdi, had led three unsuccessful campaigns against Koguryo, which contributed to his downfall. While Koguryo recognized Chinese suzerainty again in 619, it also began to build a network of defensive fortifications on its frontier.
In 642, the anti-Chinese general Yeon Gaesomun staged a coup in Koguryo and established himself as a military dictator. When Gaesomun cut off tribute from Silla to the Tang court, Taizong decided to lead a campaign against Koguryo in person. In early 645 CE, Taizong and Li Shiji invaded Koguryo territory in southern Manchuria while a large naval force attacked Koguryo’s capital, Pyongyang, from the sea. Despite initial success on land, the Tang army was held back at the fortress of Anshi while the fleet failed to achieve its objective, and Taizong reluctantly ordered a withdrawal.
Determined to reverse this humiliation, in 647 CE, Taizong launched a second invasion of Koguryo, which once again proved inconclusive. The emperor planned to raise an army of 300,000 men supported by a large armada for a third campaign in 649, but his health faltered, and he died in Chang’an in the summer of 649 at approximately 50 years of age. Tang Taizong was buried at his mausoleum of Zhaoling to the northwest of Chang’an. He was succeeded by his son Gaozong, best known as the spouse of the formidable Empress Wu Zetian.
