Yang Liangyao is not attested in any surviving history or other written source,[1] apart from a stele that was discovered in 1984 at Xiaohuyang village in the Yunyang District of Jingyang County, Shaanxi Province.
[1][3] Following the rebellion of general Zhu Ci in 782 and the capture of Chang'an by the rebels, in 784 Yang was sent in embassy to the Tibetan Empire to seek military support, in exchange for ceding the provinces of Anxi and Beiting.
[4][5] In the next year, he led an embassy to the Abbasid Caliphate via sea from Guangzhou, and was back at Chang'an in mid-788, when he was honoured as Grand Master of the Palace, and given the rank of baron of Hongnong District, with 300 households attached to his service as an appanage.
The Tang strategy, as articulated a couple of years later by chancellor Li Bi, was one of allying with the Tibetans' neighbours—the Abbasids, the Uyghur Khaganate, Indian powers, and Nanzhao—and attacking Tibet from all sides.
Three years later, he was appointed to suppress the revolt of Wu Shaocheng in Huaixi, which he did successfully through a judicious mixture of infiltrating spies among the rebels to learn their intentions, and offering them pardon and recruitment into the Imperial army.