At the end of the Western Jin Dynasty, Sima, the evil king of Langxue, was the general of Zhendong, the governor of the Yangzhou military, and stationed in Jianye (now Nanjing).

In 311 AD, Luoyang was captured by Liu Cong, and the Jin Dynasty's regime had actually been transferred to Jiankang (when the Jin Dynasty was overrun, Jiankang was changed to Jiankang). Therefore, Sima Rui was appointed as the prime minister, the governor, and the foreign military.

In 316 AD, Liu Cong captured Chang 'an, Emperor Han of Jin was captured, and Sima Rui called himself King of Jin. The Jin regime completely moved to Jiangnan.

On April 6, 317 (the ninth day of March in the first year of Jianwu in the Eastern Jin Dynasty, it has been {sys: (year (now) -317) } years) Sima Rui learned that Emperor Jin was killed by Liu Cong, so he was called the emperor, who was Emperor Jin Yuan, changed to Yuan Jianwu, and was known as the Eastern Jin Dynasty in history.