territory south of the Yellow River (except for modern Shandong, where the warlord Duan Kan (段龕) had been a nominal Jin vassal since 351 but was conquered by Former Yan's emperor Murong Jun in 356). In 357, as Emperor Mu turned 14 and went through his rite of passage (jiaguanli (加冠禮)), Empress Dowager Chu officially stripped herself of her role as regent, and moved to Chongde Palace (崇德宮), which would be her residence for the rest of her life. In 361, Emperor Mu died at the age of 18. As he had no sons, Empress Dowager Chu ordered that his cousin Sima Pi the Prince of Langye (Emperor Cheng's oldest son) be made emperor, and he took the throne as Emperor Ai. During Emperor Ai's reign As Emperor Ai was two years older than Emperor Mu and already 21 at the time of his ascension, Empress Dowager Chu did not serve as regent initially. However, in 364, when Emperor Ai became poisoned by pills given by magicians which he took while trying to seek immortality, he fell ill and could not handle matters of state. Empress Dowager Chu again served as regent at that point. After he died sonless in 365, she ordered that his younger brother Sima Yi the Prince of Langye succeed him (as Emperor Fei). During Emperor Fei's reign Similarly, because Emperor Fei was also already an adult at the time he ascended the throne, Empress Dowager Chu did not serve as regent. However, after Huan Wen's major attack on Former Yan in 369 was repelled, at much loss of life, by joint forces of Former Yan and Former Qin, he pondered ways to demonstrate that he was still in control, particularly because he was interested in usurping the Jin throne. He spread false rumors that Emperor Fei was impotent and that all his sons were actually sons of his close associates. In 371, he drafted a proposed edict for Empress Dowager Chu and submitted it to her while she was at a Buddhist shrine in her palace. She read his submission and commented that she suspected the same thing, and she signed the edict, although she added several sentences showing her grief: This widow has suffered more than a hundred kinds of grief. I consider those who have died and those who still live, and my heart is like being cut by knives. Huan was initially