Emperor Fei of Jin

Emperor Fei of Jin (; 342 – November 23, 386), personal name Sima Yi , courtesy name Yanling , was an emperor of the Eastern Jin Dynasty in ancient China. He was the younger full-brother of Emperor Ai; he was later deposed by military leader and regent Huan Wen. The title that he is normally referred to, "Emperor Fei", is not a posthumous name or temple name as is usually the case with Chinese imperial titles, but rather signified that he was deposed (with "Fei" meaning "depose(d)"). He is also commonly known by the title he was given after his removal, Duke of Haixi ; he is also the last descendant of Emperor Ming (his grandfather) to become emperor of the Eastern Jin.

Early life Sima Yi was born in 342, to Emperor Cheng and his concubine Consort Zhou, who was also the mother of his only brother, Sima Pi, who was one year older than he was. Later in 342, Emperor Cheng grew gravely ill. Typically, the throne would be passed down to a son, but Emperor Cheng's uncle Yu Bing , who wanted to control the government a little longer, suggested that since Jin was then facing the threat of Later Zhao, an older emperor was needed, and so persuaded Emperor Cheng to pass the throne to his younger brother Sima Yue the Prince of Langya, who was Yu Bing's nephew as well. Emperor Cheng agreed, and after his death, Sima Yue took the throne as Emperor Kang. Emperor Kang created Sima Yi the Prince of Donghai on 1 August 342.

In Sima Yi's youth, he went through a progression of official ranks. While he was still the Prince of Donghai, he married Yu Bing's daughter Yu Daolian as his princess consort. In 361, after the death of his cousin Emperor Mu (Emperor Kang's son) on 10 July, his older brother Sima Pi took the throne as Emperor Ai on 13 July, and he took over the greater title of Prince of Langya which Emperor Ai had previously held, on 15 July. In 365, after Emperor Ai died without a son, Sima Yi took the throne by decree of his aunt Empress Dowager Chu (Emperor Kang's wife). He created his wife Princess Consort Yu empress.

Reign Even though Emperor Fei was an adult, he did not have actual power, as not only were governmental matters largely in the hands of his granduncle Sima Yu the Prince of Kuaiji, but Sima Yu himself was not fully able to make decisions, as the paramount general Huan Wen imposed many of his own decisions on the imperial government, which had no choice but to accept.

Immediately after Emperor Fei took the throne, the important city Luoyang (which had served as Jin's capital early in the dynasty's history) fell to Former Yan, because Emperor Ai's death prevented a relief force from being dispatched.

Late in 365, the general Sima Xun, the governor of Liang Province (梁州, modern southern Shaanxi) rebelled, but he was defeated, captured, and executed in summer 366.

On 5 July 366, Empress Yu died. Emperor Fei would not have another empress for the rest of his reign. – 6 January 372

Family Empress Xiao, of the Yu clan of Yingchuan (; d. 366), aunt, personal name Daolian Meiren, of the Tian clan (; d. 372) Unnamed son (d. 372) Unnamed son (d. 372) Meiren, of the Meng clan (; d. 372) Unnamed son (d. 372)

Ancestry