Overview
Li Heng, Emperor Suzong, ruled the Tang through the worst years of the An Lushan Rebellion. His reign shows the title in a new light: the Heavenly Qaghan now depended on a steppe power, the Uyghurs, to survive.
Rise to Power
He was proclaimed emperor at Lingwu in 756 after his father Xuanzong fled to Sichuan.
Rule and Achievements
- Asked the Uyghur Khaganate for help; Uyghur cavalry helped retake Chang'an and Luoyang in 757
- Married his daughter, Princess Ningguo, to the Uyghur qaghan Bayanchur in 758; the qaghan spoke of himself and the 'Heavenly Qaghan' as the rulers of two states
- Paid heavily in silk for the alliance, which tied the Tang to the Uyghurs for the next eighty years
Legacy
He died in 762, before the rebellion was over. The records of his reign show that the steppe still used the title for the Tang emperor, but now between two equal rulers.