Wang Chengzong
In 820, Emperor Xianzong died and was succeeded by his son Emperor Muzong. Later that year, Wang Chengzong also died, and his brother Wang Chengyuan offered control of the circuit to the imperial government, and Emperor Muzong commissioned Tian Hongzheng to succeed Wang Chengzong. In 821, however, the Chengde officer Wang Tingcou mutinied and killed Tian, and then took over the circuit. Emperor Muzong declared a general campaign against Chengde, and Wu Chongyin was considered the leader of the imperial generals against Chengde. With Wang Tingcou's troop strength at its peak at the moment, Wu believed that he needed to wait out the situation, and therefore slowed his attack to try to wear out the Chengde troops. Emperor Muzong, displeased with Wu's slow progress, replaced Wu with Du Shuliang () and moved Wu to be the military governor of Shannan West Circuit (山南西道, headquartered in modern Hanzhong, Shaanxi) and the mayor of its capital Xingyuan Municipality (). When Wu arrived at the capital Chang'an, he further stripped Wu's military command and had him made a senior advisor to the Crown Prince. Subsequently, Wu was made the military governor of Tianping Circuit (天平, headquartered in modern Tai'an, Shandong).