Sima Yi (179 – 7 September 251), courtesy name Zhongda, was a general and politician of the state of Cao Wei in the Three Kingdoms period. He is perhaps best known for defending Wei from Zhuge Liang's Northern Expeditions. His success and subsequent rise in prominence paved the way for his grandson Sima Yan's founding of the Jin dynasty, which would eventually bring an end to the Three Kingdoms era. In 265 after the Jin dynasty was established, Sima Yi was posthumously honoured as Emperor Xuan of Jin with the temple name of Gaozu.