Emperor Jianwen of Jin

Emperor Jianwen of Jin, personal name Sima Yu (司馬昱), courtesy name Daowan (道萬), was an emperor of the Eastern Jin Dynasty (265-420) in China. He was the younger brother of Emperor Ming and installed by military leader Huan Wen. Prior to taking the throne, he had served in important roles in the administrations of his grandnephews Emperor Mu, Emperor Ai, and Emperor Fei. Both in his service to his grandnephews and in his own reign as emperor, he is generally viewed as a weak-willed figure who showed enough wisdom to continue to survive and extend Jin rule, but whose effectiveness was also compromised by his over-dedication to philosophical discussions of Taoism and other related philosophies.