Nanzhao takes Songping and holds Annam

Tang rule in Annam had been unsettled for decades by mutinies and the extortion of governors. In the 850s local chieftains went over to Nanzhao, and in January 861 local forces together with Nanzhao troops, more than 30,000 men by the account of the Zizhi tongjian, took Jiaozhi, the walled city of Songping, which the protector-general Li Hu soon recovered. In the winter of 862–863 Nanzhao returned with, the chronicle says, 50,000 men and besieged the city. Among the defenders was the official Fan Chuo, whose Man shu, an account of the southern peoples written soon afterwards, records the siege, including a naked foreign monk shot in the chest by the governor Cai Xi. Early in 863 the city fell; Cai Xi drowned trying to reach a boat, and more than four hundred soldiers who could find no boats turned back into the city, killed, according to the chronicle, over two thousand of the enemy and died fighting. The Zizhi tongjian adds that in its two captures of Jiaozhi Nanzhao killed or carried off nearly 150,000 people — a chronicle figure that cannot be checked. Nanzhao left 20,000 men to hold the city, but its troops plundered the countryside, and many inhabitants fled to the hills.

In 864 the court gave the command to Gao Pian, a general who had fought the Tanguts. In 865 he surprised a large enemy force busy harvesting rice and fed his troops on the captured grain; in 866, despite intrigues that briefly cost him his command, he defeated Nanzhao before Jiaozhi, took the city and executed the Nanzhao commander Duan Qiuqian and the local rebel leader Zhu Daogu. The court made Annam the Jinghai army command under Gao Pian, who rebuilt the city walls, known as Đại La. In 880 two chief ministers, urging a marriage alliance with Nanzhao, told the emperor that the wars with Nanzhao — twice in Annam and Yongzhou, once in Qianzhong and four times in Sichuan — had kept the empire in turmoil for fifteen years, emptied the treasury and driven men to banditry.