Li Yuan founds the Tang dynasty

The Sui empire, reunited in 589, began to break apart under the strain of Emperor Yang’s wars against Goguryeo and his labour levies. Peasant risings spread from 611, the general Yang Xuangan rebelled in 613, and after 616, when the emperor withdrew to Jiangdu on the Yangtze, the north was divided among rebel leaders and Sui commanders. One of them was Li Yuan, Duke of Tang and the emperor’s cousin, who held Taiyuan in modern Shanxi; prophecies that the next ruler would bear the surname Li, and the emperor’s execution of another Li family on that suspicion, gave him reason to fear for his life.

On 23 June 617 Li Yuan executed the emperor’s deputies at Taiyuan, Wang Wei and Gao Junya, and raised his army; he sent Liu Wenjing to seek the support of Shibi Khan of the Eastern Turks and on 11 August marched south-west with, according to the Old Book of Tang, 30,000 men. He defeated a Sui army at Huoyi, crossed the Yellow River and arrived before Chang’an with 200,000; the city fell on 12 December. A week later he enthroned the young prince Yang You and proclaimed Emperor Yang ‘retired emperor’, taking for himself the titles of chancellor and Prince of Tang. After news came that the emperor had been strangled at Jiangdu in a mutiny led by Yuwen Huaji on 11 April 618, Yang You abdicated, and on 18 June Li Yuan took the throne in the Taiji Hall and proclaimed the Wude era. According to the Old Book of Tang, the rising had first been planned by his son Li Shimin, the future Emperor Taizong, together with Liu Wenjing.

The new dynasty still had to fight for the empire. Li Shimin defeated Xue Rengao in the north-west in 618 and Liu Wuzhou in Shanxi in 620, and in 621 he crushed Dou Jiande at the Hulao Pass and forced Wang Shichong to surrender Luoyang. By 624 the south had been won, and in 628 the last rival, Liang Shidu, was eliminated. The Tang adopted a new calendar in 618 and a new coin, the Kaiyuan tongbao, in 621, and under Taizong (626–649) extended its power deep into Central Asia. Interrupted only by the Zhou dynasty of Wu Zetian (690–705), it ruled China until 907.