Emperor Muzong of Tang - As Crown Prince

As Crown Prince

Not much was recorded about Li Heng's life as crown prince, although it is known that in 817, the imperial consultant Wei Shou (韋綬), who was an attendant to Li Heng in his studies, drew disfavor from Emperor Xianzong for providing Li Heng with expensive food and pleasing him with humor. Emperor Xianzong removed Wei from his post as attendant, and soon sent him out of the capital Chang'an to serve as the prefect of Qian Prefecture (虔州, in modern Ganzhou, Jiangxi). Meanwhile, the powerful eunuch Tutu Chengcui had often urged Emperor Xianzong to replace Li Heng with Li Kuan (whose name had been changed to Li Yun by this point). Tutu, however, did not relent in his hopes to have Li Yun made crown prince, even by 820, when Emperor Xianzong had become seriously ill. Li Heng, worried about what would happen next, requested advice from his uncle (Consort Guo's brother) Guo Zhao (郭釗), who advised him to simply serve his father with filial piety and not worry about the rest.

By this point, Emperor Xianzong, whose illness was said to be due to alchemists' pills that were designed to achieve immortality and whose temper and rage had become uncontrolled, was causing widespread fear among the eunuchs. In spring 807, he died suddenly — and it was believed that he was assassinated by the eunuch Chen Hongzhi (陳弘志), but the eunuch suppressed an investigation into the matter, announcing that Emperor Xianzong had died from the pills' complications. In the aftermaths, the eunuchs Liang Shouqian (梁守謙), Ma Jintan (馬進潭), Liu Chengjie (劉承偕), Wei Yuansu (韋元素), and Wang Shoucheng, who supported Li Heng, killed Tutu and Li Yun, allowing Li Heng to take the throne (as Emperor Muzong). (There were suspicions by some, including by Li Heng's younger brother Li Yi, who would later become emperor, that Li Heng and his mother Consort Guo were involved in Emperor Xianzong's assassination.)