[3] When the imperial government declared a general campaign against Wang Chengzong's former ally Li Shidao the military governor of Pinglu Circuit (平盧, headquartered in modern Tai'an, Shandong), he advised Wang Chengzong to send 2,000 to aid the imperial campaign against Li.
[8] In winter 820, Wang Chengzong died, and initially, his subordinates kept his death a secret.
He also secretly submitted a petition to Emperor Muzong that the imperial government send a permanent replacement for him.
In response, Emperor Muzong issued a number of military governor commissions involving Chengde and nearby circuits — transferring Tian Hongzheng the military governor of nearby Weibo Circuit (魏博, headquartered in modern Handan, Hebei) to Chengde, making Wang Chengyuan the military governor of Yicheng Circuit (義成, headquartered in modern Anyang, Henan), transferring Liu Wu the military governor of Yicheng to Zhaoyi Circuit (昭義, headquartered in modern Changzhi, Shanxi), transferring Li Su the military governor of Wuning Circuit (武寧, headquartered in modern Xuzhou, Jiangsu) to Weibo, and making Tian Hongzheng's son Tian Bu the military governor of Heyang Circuit (河陽, headquartered in modern Jiaozuo, Henan).
Wang Chengyuan urged them to accept, citing the example of how Li Shidao's officers had initially not allowed him to accept imperial orders, but later killed him and surrendered to imperial forces when they attacked.
On the way to Fufang, he went to Chang'an to pay homage to Emperor Muzong, who approved of his behavior and met him on several occasions.
Soon thereafter, he was transferred to Fengxiang Circuit (鳳翔, headquartered in modern Baoji, Shaanxi).
At that time, because Fengxiang Circuit's land was flat, Tufan forces often were able to invade without obstacles.