Emperor Hui of Jin

Emperor Hui of Jin, personal name Sima Zhong (司馬衷), courtesy name Zhengdu (正度), was the second emperor of the Western Jin dynasty. Emperor Hui was a developmentally disabled ruler, and throughout his reign, there was constant internecine fighting between regents, imperial princes, and his wife Empress Jia Nanfeng for the right to control him, causing great suffering for the people and greatly undermining the stability of the Western Jin dynasty, eventually leading to rebellions of the Five Barbarians that led to Jin's loss of northern and central China and the establishment of the competing Sixteen Kingdoms. He was briefly deposed by his granduncle Sima Lun, who usurped the throne himself, in February 301, but later that year was restored to the throne and continued to be the emperor until January 307, when he was poisoned, likely by his last regent Sima Yue.