Emperor Cheng of Jin

Emperor Cheng of Jin (Chinese: 晉成帝; pinyin: Jìn Chéng Dì; Wade–Giles: Chin Ch'eng-ti; 321 – 26 July 342), personal name Sima Yan (司馬衍), courtesy name Shigen (世根), was an emperor of the Eastern Jin Dynasty (265-420). He was the eldest son of Emperor Ming and became the crown prince on April 1, 325. During his reign, the administration was largely dominated by a succession of regents—initially his uncle Yu Liang, then Wang Dao, then the joint administration of He Chong (何充) and another uncle Yu Bing (庾冰). He became emperor at age four, and soon after his accession to the throne, the disastrous rebellion of Su Jun weakened Jin forces for decades.

Sima Yan was born as the oldest son of Emperor Ming of Jin, who was crown prince at that time, by his wife Crown Princess Yu Wenjun, in 321. After Emperor Ming took the throne in 323 following the death of his father Emperor Yuan, he created Crown Princess Yu empress, but did not immediately create Prince Yan crown prince, until 325.

In fall 325, Emperor Ming grew ill. He entrusted the four-year-old Crown Prince Yan to a group of high-level officials, including Sima Yang (司馬羕) the Prince of Xiyang, Wang Dao, Bian Kun (卞壼), Chi Jian (郗鑒), Lu Ye (陸瞱), Wen Jiao, and Empress Yu's brother Yu Liang, perhaps intending that they lead by group with a balance of power. He died soon thereafter. Crown Prince Yan took the throne as Emperor Cheng.

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