郑注
In 834, Zheng was made the minister of census (戶部尚書, "Hubu Shangshu"). Later in the year, Li Deyu was stripped of his chancellor post, and Li Zongmin, who again became chancellor, worked in conjunction with Emperor Wenzong's close associates Li Xun and Zheng Zhu to eject Li Deyu's allies out of important posts. Zheng Tan was thereafter made "Mishu Jian" (), the head of the Palace Library. In summer 835, after Li Zongmin and his ally Yang Yuqing () offended Emperor Wenzong and were exiled, Zheng was made the minister of justice (刑部尚書, "Xingbu Shangshu"). In winter 835, he was made "You Pushe" (), one of the heads of the executive bureau (尚書省, "Shangshu Sheng") as well as the principal of the imperial university (國子祭酒, "Guozi Jijiu").