Coup by General Yŏn Kaesomun

In 642 CE, General Yeon Gaesomun carried out a coup in the Goguryeo Kingdom, overthrowing King Yeongnyu and establishing a new system of military-dominated rule. This event marked a significant shift in Goguryeo’s internal governance during a period of increasing tension with the Tang Dynasty. The coup developed from a division within the Goguryeo leadership. One faction, associated with Yeon Gaesomun, supported a strong military stance against Tang China, while another group, aligned with King Yeongnyu, favored diplomatic engagement. According to historical records, Yeon acted amid concerns that he might be removed from power by the court. In 642, Yeon Gaesomun organized a gathering attended by leading officials. During this event, his forces carried out a coordinated attack, killing numerous members of the opposing faction. Following this, Yeon moved against the royal palace, where King Yeongnyu was killed. Contemporary sources describe the king’s death as violent, though details vary across records. After seizing control, Yeon Gaesomun placed King Bojang, a relative of the previous king, on the throne. While Bojang held the formal title of king, real authority remained with Yeon, who assumed the position of Tae Mangniji, the highest military office in Goguryeo. This arrangement effectively placed the state under centralized military leadership. Yeon Gaesomun’s rule continued until his death in 666 CE. During this period, Goguryeo maintained resistance against external pressures, particularly from the Tang Dynasty, but internal divisions following his death contributed to the kingdom’s decline and eventual fall in 668.