Cui Yan
In 820, Emperor Xianzong died and was succeeded by his son Emperor Muzong. Emperor Muzong was considered pleasure-loving, and in winter 820, there was an occasion when Emperor Muzong met with the imperial officials in the palace. Zheng Tan, his colleague Cui Yan (), and three other advisory officials took the opportunity to advise him that he was spending too much time in feast and games, and was overly exhausting the imperial treasury with his rewards to his favorites. Emperor Muzong was much surprised and initially displeased by the advice, and asked the chancellor Xiao Mian who these officials were. Xiao informed him that these were advisory officials. Emperor Muzong thus understood that they were giving him advice, and he dismissed them with kind words, but did not actually carry out their advice.