The Tang Empire: Expansion, Rebellion and Regional Power

The Tang dynasty ruled from 618 to 907, interrupted by Wu Zetian’s Wu Zhou dynasty from 690 to 705. Its history was shaped by the relationship between the imperial court and the commanders responsible for defending distant frontiers. Tang armies extended the dynasty’s reach across parts of Central and East Asia, but the An Lushan rebellion of 755–763 weakened central authority. In the decades that followed, powerful regional military governors became harder for the court to control, helping to bring the dynasty to an end.

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From the fall of the Sui to a Tang court

The Tang emerged amid the collapse of the Sui dynasty. Li Yuan, a Sui governor and military leader, rebelled in 617 and took Chang’an, the western capital. After the Sui emperor’s death, Li Yuan proclaimed the Tang dynasty in 618. His son Li Shimin, a leading commander in the wars that consolidated the new regime, forced his father to abdicate in 626 after killing two of his brothers in the Xuanwu Gate Incident. Li Shimin then ruled as Emperor Taizong.

The Tang court combined imperial authority with a civil administration staffed by officials. Examinations and recommendations provided routes into government, while the emperor and senior ministers directed policy. The court also depended on military commanders to defend far-flung borders. This arrangement could extend Tang power, but it gave frontier commanders substantial responsibility and, in some regions, growing influence over troops and local affairs.

Expansion and the limits of frontier rule

Under Taizong and his successors, Tang forces defeated the Eastern Turks and campaigned against states and powers in the western regions. The defeat of the Western Turkic Khaganate in 657 extended Tang influence into Central Asia. In the east, Tang forces joined with Silla against the Korean kingdoms of Baekje and Goguryeo. Goguryeo fell in 668, but Tang forces were driven out of Korea by Silla by 676.

Tang authority beyond the empire’s central provinces took different forms. The court established protectorates in some frontier regions, where officials could respond to local problems with considerable autonomy. Other rulers sent tribute or maintained diplomatic relations without being governed as ordinary Tang provinces. The reach of the court was therefore not the same as direct control everywhere. Tang and Tibetan forces repeatedly contested territory in Inner and Central Asia, while Tang forces suffered a defeat by an Abbasid-led army at Talas in 751, weakening their position west of the Tarim Basin. The Tang retained territories in the Tarim Basin for a time, but later withdrew western garrisons during the An Lushan rebellion.

Wu Zetian and struggles at court

Power at court was not confined to emperors and senior male officials. Wu Zetian, who entered the palace as a consort of Emperor Gaozong, became an influential decision-maker as his health failed. In 690 she took the throne in her own name and established the Wu Zhou dynasty, formally interrupting Tang rule. She remained in power until a palace coup forced her to yield in 705, when the Tang dynasty was restored.

Contests for authority continued after Wu’s fall. In 710, Li Longji, later Emperor Xuanzong, overthrew Empress Wei’s faction and helped restore his father, Emperor Ruizong, to the throne. Ruizong abdicated in 712, and Xuanzong then ruled for more than four decades. The political strength of the court during his reign varied over time. In its early years the dynasty prospered, but later Xuanzong relied heavily on powerful ministers and frontier commanders, whose interests could diverge from those of the central government.

Frontier commanders and the revolt of 755

The office of jiedushi, or regional military governor, became increasingly important from the early eighth century. These governors commanded troops in designated regions, especially along the frontiers. The Tang had also shifted towards longer-serving soldiers: in 737 Xuanzong extended the use of long-service frontier troops, reducing reliance on rotating farmer-soldiers for distant defence. Such forces could be more experienced, but commanders with lasting control over frontier armies also had a powerful base of their own.

An Lushan, a general of Sogdian and Turkic background, held several northern commands, including Fanyang, Pinglu and Hedong. His position gave him authority over a large body of frontier troops. In December 755 he rebelled and marched from Fanyang. His forces took Luoyang in January 756, where he proclaimed a new Yan dynasty, and then advanced towards Chang’an. Tang forces were defeated at Tongguan, opening the route to the capital. Xuanzong fled towards Sichuan. During the flight, his guards killed the minister Yang Guozhong and demanded the death of Yang Guifei, whom the emperor ordered to be executed.

The Tang lost Chang’an in 756, but the rebellion did not secure control of the empire. Defenders at Yongqiu blocked the rebels’ advance south, and Tang forces regrouped under Xuanzong’s son, Emperor Suzong. With help from Uyghur forces, the Tang recovered Chang’an and Luoyang in 757. The conflict continued under rebel leaders An Qingxu, Shi Siming and Shi Chaoyi. Rivalries among them weakened Yan, and Shi Chaoyi’s death by suicide in 763 ended the rebellion.

The fighting brought displacement, famine and damage to infrastructure, while the upheaval disrupted the government’s ability to register households and collect taxes. The Tang survived, but it could not simply restore its earlier control. Tibetan forces took advantage of the crisis, briefly capturing Chang’an in 763, and the court withdrew troops from some western territories.

Regional military power and recovery

After the rebellion, the court relied on former Yan generals and other commanders to govern troubled regions. Some retained their armies and authority as jiedushi. In practice, these governors could collect taxes, maintain troops and, in some cases, pass their positions to heirs. This arrangement helped the weakened court secure local cooperation, but it also allowed regional military governments to become less dependent on appointments from the capital. Several circuits in Hebei, in particular, remained difficult for the court to control.

The shift was not an uninterrupted decline. Emperor Xianzong, who ruled from 805 to 820, led campaigns against provinces resisting central authority and restored civil officials to some regional administrations. The government also adapted its finances. In 780, a two-tax system assessed households and cultivated land, with collections in summer and autumn. Money became more important in assessment, while grain and textiles also remained part of payments. The state’s salt monopoly became a major source of revenue, helping the court continue to fund its administration and military campaigns. These measures supported recovery, but later rulers did not maintain the same degree of control over regional commanders.

Rebellion and the end of the dynasty

The Huang Chao rebellion of 874–884 again devastated large areas of northern and southern China. Rebel forces sacked Chang’an and Luoyang, and the Tang court’s ability to command the empire was further reduced. Regional military leaders increasingly determined events beyond the capital. Li Keyong, a Shatuo commander whose forces helped suppress Huang Chao, and Zhu Wen, a former rebel who joined the Tang side, became major rivals in the north.

Zhu Wen gained control of the emperor after struggles with rival commanders and court factions. In 904 he forced Emperor Zhaozong and the court from Chang’an to Luoyang, closer to his own power base. He then had Zhaozong assassinated and installed the young Emperor Ai. In 907 Zhu Wen deposed Ai and founded Later Liang. The Tang ended, and competing dynasties and regional states divided its former territory.

For the wider setting, see Tang China: History, Government and Society.