李吉甫
Traditionally, the seeds of the Niu–Li factional strife were seen to have been sown in 808, when Emperor Xianzong held a special imperial examination for the examinees to give honest criticism of government. The officials in charge of the examination, Wei Guanzhi and Yang Yuling (楊於陵), selected three examinees who gave blunt criticism—Niu Sengru, Huangfu Shi (皇甫湜), and Li Zongmin—for top marks. However, Chancellor Li Jifu was stung by the criticism they provided and viewed it as a personal attack against him. Li Jifu tearfully complained to Emperor Xianzong that the reviewers of the scores that Wei and Yang gave the imperial scholars - Pei Ji and Wang Ya — had conflicts of interest, as Huangfu was Wang's nephew. As a result of his accusations, Pei, Wang, Yang, and Wei were each demoted, with Wei initially demoted to be the prefect of Guo Prefecture (果州, in modern Nanchong, Sichuan), and then further moved to be the prefect of Ba Prefecture (巴州, in modern Bazhong, Sichuan). Niu, Huangfu, and Li Zongmin were not exiled, but were said in the "Zizhi Tongjian" to be effectively stalled in their careers, forcing them to find governmental positions themselves under regional governors. Despite this, Li Jifu's son Li Deyu viewed the insult on his father to be too great to bear, and thereafter an enmity developed between Li Deyu and those he viewed as having criticized his father unfairly.