Gao Yun (Northern Yan)

Gao Yun (高雲), (Go Un (고운) in Korean) (died 409), at one time Murong Yun (慕容雲), courtesy name Ziyu (子雨), formally Emperor Huiyi of (Later)/(Northern) Yan ((後)/(北)燕惠懿帝), was an emperor who, depending on the historian's characterization, was either the last emperor of the Xianbei state Later Yan, or the first emperor of its succeeding state Northern Yan. He was ethnically Korean and a descendant of the royal house of Goguryeo, whose ancestors were captured by Former Yan. He was adopted into the Later Yan imperial house after helping the emperor Murong Bao (Emperor Huimin) put down a rebellion by Murong Bao's son Murong Hui. He became emperor after the people rebelled against the despotic rule of his adoptive uncle Murong Xi (Emperor Zhaowen), and during his reign, he used the title "Heavenly Prince" (Tian Wang). In 409, he was assassinated, and after a disturbance, was replaced by his ethnic Han chinese general Feng Ba (Emperor Wencheng).

Gao Yun's ancestors were from the Goguryeo royal house. When Murong Huang defeated Goguyreo forces and temporarily occupied its capital Wandu, he took many members of the Goguryeo royal house captive and moved them to Qingshan (青山, in modern Jinzhou, Liaoning), and their descendants became Former Yan and Later Yan subjects. Because the first character of Goguryeo's name, in Chinese, was Gao (高), they largely took Gao as their family name.

As of 397, Gao Yun was a mid-level official in the administration of Murong Bao (Emperor Huimin), when Murong Bao, under military pressure by Northern Wei, abandoned the capital Zhongshan (中山, in modern Baoding, Hebei) and sought to take refuge at the old Former Yan capital Longcheng (龍城, also in Jinzhou). On the way, his son Murong Hui, resentful that his younger brother Murong Ce (慕容策) was made crown prince over him, rebelled, and while Murong Bao was able to reach Longcheng, Murong Hui put Longcheng under siege. During one night, Gao Yun led about 100 soldiers and made a surprise attack on Murong Hui's camp, causing Murong Hui's army to collapse. Murong Hui fled to Zhongshan and was killed there. For Gao Yun's contributions, Murong Bao created him the Duke of Xiyang and adopted him as his own son, and so his name was changed to Murong Yun. It was around this time that he befriended another general, Feng Ba, as Murong Yun was not looked up favorably by others because he was a man of few words, but Feng Ba saw that he had wisdom and tolerance.

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