With the possible exception of Ge Hong, the first author known to have attributed the composition of the whole Cantong qi to Wei Boyang is Liu Zhigu 劉知古, a Taoist priest and alchemical practitioner who was received at court by Emperor Xuanzong around 750 CE.
In 733 Mes-ag-tshoms wrote to the Chinese emperor Xuanzong (r. 712-756) stating that China and Tibet were equally great kingdoms and hoping that peace would endure.
Indeed, troubled by an increasingly confrontational Balhae (which had actually launched a seaborne attack against Tang in 733), in 733 the Tang emperor Xuanzong enfeoffed King Seongdeok as Military Commander of Ninghai (Ninghai junshi 寧海軍使) with orders to chastise the Balhae/Malgal state.
Emperor Xuanzong of Tang | Xuanzong | Emperor Xuānzong of Tang |
Emperor Xuānzong was impressed, comparing him to the prominent Zhao generals Lian Po and Li Mu, and asked him whether he would be willing to accept the Binning assignment.
In 763, when Emperor Xuanzong's grandson Emperor Daizong was emperor, Tibet launched an attack against Chang'an, and Emperor Daizong was forced to flee to Shan Prefecture (陝州, in modern Sanmenxia, Henan).
After Li Chengqian's grandson Li Shizhi became chancellor during the reign of Li Chengqian's grandnephew Emperor Xuanzong, he often spoke to Emperor Xuanzong in defense of his grandfather.
In 755, the general An Lushan rebelled at Fanyang, and by summer 756, the forces of his new state of Yan were approaching the Tang capital Chang'an, forcing Emperor Xuanzong to flee to Chengdu.
Yang Guozhong (楊國忠) is the chancellor during Emperor Xuanzong's reign.
Emperor Xuanzong's son and crown prince Li Heng, however, did not follow him to Chengdu, but fled to Lingwu instead, where he was declared emperor (as Emperor Suzong).
Emperor Xuanzong issued an edict praising him for his filial piety, and made him the commandant at Hong Prefecture (洪州, roughly modern Nanchang, Jiangxi).