aside from the emperor himself, Guo Ziyi was the only one that the common people were willing to follow. Suzong, worried by Guo's popularity, used this as a pretext to decrease Guo's authority, demoting him while generously rewarding the other jiedushi. Nestorian Christianity The Nestorian Church of the East Christians like the Bactrian Priest Yisi of Balkh helped the Tang dynasty general Guo Ziyi militarily crush the An Lushan rebellion, with Yisi personally acting as a military commander and Yisi and the Nestorian Church of the East were rewarded by the Tang dynasty with titles and positions as described in the Nestorian Stele. Under Emperor Suzong Although the An Lushan Rebellion was finally put down in 763, the Tang was immediately confronted by another threat from the Tibetan Empire. Tibet had benefited from the Tang's prosperous period when trade with the Tang was frequent. During the An Lushan Rebellion, it reached the height of its power, and betrayed the peace treaty with the Tang by supporting the rebels. Weakened by the rebellion, Tang border garrisons were unable to resist Tibetan raids into their territory. Most jiedushi were not ethnically Chinese and had little incentive to defend the Tang Empire, especially when it was ruled by a weak emperor. In response, Suzong re-promoted Guo Ziyi, but only as a military figurehead with no authority, in the hope that merely the threat of sending Guo against them would keep the Tibetans at bay. In 762, a general named Wang Yuanzhi murdered Li Jingzhi, the jiedushi of Shaanxi, claiming that the troops were still so loyal to Guo that they demanded he be reinstated as jiedushi. Suzong was forced to return Guo Ziyi to his former position. When Guo Ziyi arrived, however, instead of thanking Wang he condemned the general for his disloyalty in killing his commander. He also pointed out that such an act disrupted the chain of command, which might embolden the Tibetans to attack. General Wang submitted to his mistakes and committed suicide. Guo Ziyi quickly assumed command of the post and the Tibetans ceased their attacks. Under Emperor Daizong and Tibetan Invasion Not long after, Suzong died and was succeeded by his son Emperor Daizong of Tang. The new emperor was worried about Guo Ziyi's fame and called him back to Chang'an. Guo Ziyi advised the emperor to take a note of the threat posed by the Tibetans, but