Cheng Yuanzhen

Cheng Yuanzhen (程元振) (died 764?) was a eunuch official of the Chinese dynasty Tang Dynasty. He was exceedingly powerful early in the reign of Emperor Daizong and was said to, in his attempts to consolidate his power, have killed or demoted a number of key generals and officials on his own whim, and thus drew the hatred from the other officials and generals. In 763, he was blamed for not warning Emperor Daizong about the Tubo invasion that eventually caused the capital Chang'an to fall to Tubo forces, forcing Emperor Daizong to flee. Emperor Daizong exiled him, and he died in exile.

Cheng Yuanzhen was from Jingzhao Municipality (京兆) -- the special municipality centered on the Tang capital Chang'an. He was a eunuch from his youth and served at the eunuch bureau (內侍省, Neishi Sheng), eventually rising to be the commander of the imperial guard archer corps (內射生使, Nei Shesheng Shi) as well as the deputy director of the imperial stables, under the powerful eunuch Li Fuguo, late in the reign of Emperor Suzong.

In summer 762, Emperor Suzong was seriously ill, near death. By this point, Emperor Suzong's wife Empress Zhang, who was previously allied with Li Fuguo, was no longer allied with him, and she tried to enter into an alliance with Emperor Suzong's son (not her son) the crown prince Li Yu, to kill Li Fuguo and Cheng Yuanzhen and seize power. Li Yu declined, and she then entered into an alliance with Li Yu's younger brother Li Xi (李係) the Prince of Yue, trying to lay a trap for Li Fuguo (and possibly Li Yu). When she issued an edict in Emperor Suzong's name summoning Li Yu, Cheng found out about her plan and detained Li Yu, escorting him to the imperial guard headquarters. He and Li Fuguo then led troops into the palace and arrested Empress Zhang and Li Xi. Upon Emperor Suzong's death, Li Fuguo executed Empress Zhang, Li Xi, and Li Xian (李僩) the Prince of Yan, and then declared Li Yu emperor (as Emperor Daizong).

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