Zhao Gao 趙高 (d. 207 BCE) was a eunuch and powerful minister at the court of the emperors of the Qin dynasty 秦 (221-206 BCE). He was a descendant of the house of Zhao 趙. His mother had come to Qin as a prisoner of war and served in the royal palace of Qin, together with her sons. Zhao Gao was therefore initiated into the innermost secrets of the royal family, as well as the court politics.
King Ying Zheng 嬴政 (r. 246/221-210 BCE), the eventual First Emperor of Qin 秦始皇, appointed him director of the livery office (zhongchefu ling 中車府令). Zhao Gao stood at the same time in the service of Prince Huhai 胡亥, second son of King Zheng. Zhao committed some offense, and after his case had been investigated by Meng Yi 蒙毅, he was sentenced to death penalty. The emperor felt pity for his valiant eunuch, pardoned him and reinstalled him into his former positions. Later on he was even entrusted with the imperial seals.
In 210, during the inspection tour to the southeast, the emperor fell sick and made his testament. He wanted Prince Fusu 夫蘇 succeed him, the military power entrusted into the hands of general Meng Tian 蒙恬, and ordered Zhao Gao to arrange the funeral. Yet Zhao Gao, after the First Emperor was deceased, secretly plotted with Counsellor-in-chief, Li Si 李斯, and Prince Huhai, to forge the testament and have Huhai mount the throne. The death of the emperor was kept secret, and with the imperial seals in his hands, Zhao Gao forged an imperial decree ordering Prince Fusu and Meng Tian to commit suicide.
Back to the capital Xianyang 咸陽 (modern Xianyang, Shaanxi), Huhai mounted the throne as the Second Emperor of Qin 秦二世皇 (r. 209-207), and Zhao Gao was made chamberlain for attendance (langzhong ling 郎中令). Zhao Gao was able to totally dominate the Second Emperor and had all potential claimants to the throne, and his own enemies, executed. When officials and nobles remonstrated to the court, Zhao Gao suggested the emperor not to keep court and instead to stay in the inner quarters. Meanwhile, the general situation in the empire worsened.
Officials openly started complaining, the people rebelled against the burden of corvée labour to built the Great Wall and the Epang Palace 阿房宮, and two nobles, Chen Sheng 陳勝 and Wu Guang 吳廣, declared the Qin dynasty illegal. Counsellor to the right Feng Qubing 馮去病 and general Feng Que 馮卻, admonishing the emperor and thus challenging the power of Zhao Gao, were executed. Zhao Gao eliminated his accomplice Li Si by charging him of treason and having him cut in two halves. General Zhang Han 章邯 was defeated by the rebel Xiang Yu 項羽 and surrendered.
Zhao Gao declared himself central Counsellor-in-chief (zhong chengxiang 中丞相). He demonstrated his boundless power by openly calling a deer a horse. Officials opposing him were executed. Only when Liu Bang 劉邦, the eventual founder of the Han dynasty 漢 (206 BCE-220 CE), defeated the Qin armies at Xiawuguan 下武關 Zhao Gao started fearing for his power. He made the emperor believe that the palace was surrounded by the enemy and forced him to commit suicide.
When Zhao Gao he wanted to declare himself emperor, he did not find enough supporters, and instead had the late emperor's nephew, still a child, made king of Qin, but not emperor. The young ruler, as the righteous ruler, found enough help to have Zhao Gao executed and his family extinguished for three generations (sanzu 三族).