Yeon Gaesomun’s Coup

Yeon Gaesomun killed King Yeongnyu and his opponents, enthroned King Bojang and ruled as Dae-mangniji (supreme minister).

King Yeongnyu and his nobles favoured peace with Tang and are said to have plotted to kill Yeon Gaesomun, the powerful chief of the Western Division. Learning of it, Yeon summoned the ministers to a military review in the tenth month of 642, killed about a hundred of them, then entered the palace and killed the king. He enthroned the king’s nephew Jang as King Bojang and made himself Dae-mangniji, holding both military and civil power.

Yeon brought Daoist priests and the Daodejing from Tang and promoted Daoism. Abroad he took a hard line: he refused Kim Chun-chu of Silla, who came seeking help that year, and rejected Tang’s demand to stop attacking Silla. Emperor Taizong used the coup as a pretext to invade in 645 (Siege of Ansi). After Yeon’s death in 665 his sons’ struggle for power led to Goguryeo’s fall.