Guyuk Khan vs King Injong of Goryeo

Güyük was elected as the third Great Khan of the Mongol Empire at a kurultai near the Mongol capital Karakorum. His election was supported by his mother Töregene, who had served as regent, but was opposed by Batu, leading to tensions.

Güyük received the Franciscan envoy John of Plano Carpini at his court, who delivered a letter from Pope Innocent IV demanding the Mongols cease their invasions. Güyük's reply demanded the Pope's submission to Mongol authority, reflecting Mongol imperial ideology.

Güyük planned a military campaign against his cousin Batu, ruler of the Golden Horde, due to Batu's refusal to recognize his authority. The conflict was averted when Güyük died in 1248, but it deepened the rift between the Toluid and Jochid lines.

Güyük died suddenly in 1248 while marching west to confront Batu, possibly poisoned. His death left the empire without a clear successor, leading to a regency by his widow Oghul Qaimish and eventually the election of Möngke in 1251.

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.