Liu Zongyuan
By the end of Emperor Dezong's "Zhenyuan" era (785-805), Cheng was serving as an imperial censor with the title "Jiancha Yushi" (). He was then made the official in charge of the directory of salt and iron monopolies and grain supplies' facility at Yangzi (揚子, in modern Yangzhou, Jiangsu). Around that time, he also became an associate of Wang Shuwen, who was a close associate of then-crown prince Li Song, along with such other junior officials as Wei Zhiyi, Lu Chun (), Lü Wen (), Li Jingjian (), Han Ye (), Han Tai (), Chen Jian (), Liu Zongyuan, Liu Yuxi, and LIn Huai ().