King Injong of Goryeo

King Injong's early reign was marked by factional struggles between the royal in-laws and scholar-officials. A coup attempt by the Yi Ja-gyeom faction was thwarted, but the power struggles weakened the throne and set the stage for later military interventions.

Buddhist monk Myocheong led a rebellion in Seogyeong (Pyongyang), advocating moving the capital there and launching a northern campaign against the Jin dynasty. King Injong initially supported Myocheong but later ordered the rebellion suppressed. The revolt was crushed after a year.

King Injong dispatched General Kim Bu-sik to crush the Myocheong rebellion. The royal forces besieged Seogyeong and defeated the rebels. Myocheong was killed. The victory reaffirmed the capital at Gaegyeong and strengthened the authority of the civil bureaucracy.

Under King Injong's patronage, the scholar-official Kim Bu-sik completed the Samguk Sagi (History of the Three Kingdoms). This is the oldest extant history of Korea, covering the Three Kingdoms period. It was written in Classical Chinese and based on earlier records.