Sima Zhao 司馬昭 (211-265), courtesy name Zishang 子上, was a powerful general under the Wei dynasty 曹魏 (220-265) during the Three Kingdoms period 三國 (220-280). He was the second son of the the regent Sima Yi 司馬懿 (179-251).
During the reign of Emperor Ming 魏明帝 (r. 226－239 CE) he was granted the title of Neighbourhood Marquis of Xincheng 新城鄉侯 and under Emperor Cao Fang 曹芳 (r. 239-254) made Leader of Court Gentlemen for the agriculture office (diannong zhonglangjiang 典農中郎將) in Luoyang 洛陽, and then promoted to the office of cavalier attendant-in-ordinary (sanji changshi 散騎常侍).
Sima Zhao participated in the military campaign of regent Cao Shuang 曹爽 (d. 249 CE) against the empire of Shu 蜀 in Sichuan. Two times, Sima Zhao was the highest commander in operations against the Shu general Jiang Wei 薑維 (202-264), and was rewarded with the title of General of the Guards (wei jiangjun 衛將軍).
When his older brother Sima Shi 司馬師 (208-255) died, Sima Zhao inherited the post of General-in-chief (da jiangjun 大將軍), Overseer of the Imperial Secretariat (lu shangshu shi 錄尚書事) and that of regent for the infant emperor Cao Mao 曹髦 (r. 254-260 CE). In 256 he acquired the title of Area Commander-in-chief (da dudu 大都督). Sima Zhao from then on systematically worked towards replacing the Wei dynasty.
This was a well-known fact, and therefore general Zhuge Dan 諸葛誕 (d. 258) sought in 257 for support in the empire of Wu 吳 and indeed was able to rise and army that would challenge the power of the family Sima. Sima Zhao thereupon ordered the emperor and his empress to initiate a punitive campaign to the southeast. With this tactic, Sima Zhao, the real commander, had the emperor around him and could use him as a hostage.
The rebellion of Zhuge Dan was indeed put down, but Cao Mao was no longer willing to play the puppet of Sima Zhao. The sovereign therefore ordered his personal guard to attack Sima Zhao, but the regent was prepared and had one of his retainers, Cheng Ji 成濟 (d. 260), assassinate the emperor. Sima Zhao enthroned Prince Cao Huan 曹奐 (Emperor Yuan 魏元帝, r. 260-265) as the next emperor.
In 263 Sima Zhao, meanwhile advanced to the post of Counsellor-in-chief (xiangguo 相國), sent out the generals Deng Ai 鄧艾 (197-264), Zhuge Xu 諸葛緒 (dates unkown) and Zhong Hui 鍾會 (225-264) to conquer the state of Shu. The campaign was successful, and of the Three Kingdoms, only two were left.
In the same year Sima Zhao arranged his endowment with the title of Duke of Jin 晉, which gave him the ressources of a territory encompassing ten commanderies (approx. size of a modern province). A year later he had himself promoted to the status of prince (wang 王) and his territory was enlarged by a further lot of ten commanderies.
After Sima Zhao's death, his son Sima Yan 司馬炎 (Emperor Wu of Jin 晉武帝, r. 265-290) inherited the title and eventually ended the Wei dynasty, proclaiming that of Jin.
The posthumous title of Sima Zhao was first Prince Wen of Jin 晉文王, and then Emperor Wen of Jin 晉文帝.