Niu Sengru
In 821, the director of salt and iron monopolies, Wang Bo, increased the tea tax by 50%. Li Jue submitted a petition, arguing that the tax rate was too high, but his argument was not accepted, as Wang Bo had increased the tax in order to pay for Emperor Muzong's palace construction projects. As Li Jue's repeated advice was not accepted, he left the capital Chang'an to serve as the magistrate of Xiagui County (下邽, in modern Weinan). Later, during the reign of Emperor Muzong's son Emperor Jingzong of Tang, when the former chancellor Niu Sengru served as the military governor of Wuchang Circuit (武昌, headquartered in modern Wuhan, Hubei), he invited Li Jue to serve as his secretary.