Wang Chengzong
In 809, after the death of Wang Shizhen the military governor of neighboring Chengde Circuit (成德, headquartered in modern Shijiazhuang, Hebei), Emperor Dezong's grandson Emperor Xianzong, then emperor, was taking a harder line against the circuits acting as semi-independent states, and for months he refused to approve the succession of Wang Shizhen's son Wang Chengzong. Emperor Xianzong finally agreed after Wang Chengzong agreed to allow two of Chengde's prefectures, De (德州, in modern Dezhou, Shandong) and Di (棣州, in modern Binzhou, Shandong) be separated into a different circuit under imperial control, to be named Baoxin Circuit (保信, to be headquartered at De Prefecture). He made Xue Changchao () the prefect of De Prefecture, whose wife was from the Wang clan, the military governor of the new circuit. However, when Tian received news of this in advance of the news arriving at Chengde, he informed Wang Chengzong that Xue had betrayed him. In response, Wang Chengzong had Xue arrested and refused to submit the two prefectures.