King Wonjong of Goryeo

King Wonjong sent his son (future King Chungnyeol) as a hostage to the Mongol court and agreed to Goryeo becoming a vassal state of the Mongol Empire. This ended decades of military resistance and established a tributary relationship that lasted for nearly a century.

After the death of King Gojong, Wonjong returned from the Mongol court where he had been held as a hostage. He was installed as king with Mongol approval, marking the beginning of direct Mongol influence over Goryeo's throne.

King Wonjong ordered the dissolution of the Sambyeolcho, a elite military unit that resisted Mongol domination. The Sambyeolcho rebelled and held out on Jeju Island until 1273, when Mongol-Goryeo forces crushed them, ending organized military opposition to Mongol rule.