Zhang Yichao drives the Tibetans out of Dunhuang

Dunhuang had been in Tibetan hands since the late 8th century, when it surrendered after a long siege. The Tibetans organised its people into units of their own pattern but relied on the leading local families, and under Ralpachen Dunhuang’s scribes copied Buddhist sutras by the thousand on royal commission. According to the New Book of Tang, the townspeople wore Tibetan dress, but at the seasonal sacrifices to their ancestors they put on Chinese clothes and wept as they put them away again. When the empire fell into civil war after 842 and its frontier generals fought each other, Tibetan control of the Hexi Corridor weakened.

In 848, Dunhuang documents relate, Zhang Yichao and other local leaders rose in revolt. In the words of the Zizhi tongjian, one day he led his men in armour, shouting, to the gate of the prefecture; the Chinese inhabitants all joined him, and the Tibetan commander fled in alarm. Zhang took charge of the town, by 850 had also taken Guazhou, Ganzhou, Suzhou and Yizhou, and sent envoys to the Tang; carrying his letter hidden in their staffs, they made their way north-east to the frontier fortress of Tiande, and the Tang histories record his submission in 851, when the garrison there reported their arrival. That year, according to the Zizhi tongjian, his elder brother brought the maps and registers of eleven prefectures to Chang’an, and at the end of 851 the court created the Guiyi (“Returning to Righteousness”) Army at Shazhou with Zhang as its military governor.

Zhang Yichao later took Liangzhou as well and fought both Tibetan bands and Uyghurs; in 867 he went to Chang’an, leaving Dunhuang to his nephew Zhang Huaishen. A mural in Mogao Cave 156 shows his army on the march. The Guiyi regime remained a Chinese outpost on the Silk Road, nominally loyal to the Tang and its successors; in the early 10th century the Cao family replaced the Zhang, and the regime lasted until the Tangut conquest in the 1030s.