The Mongol Empire launched several invasions against Korea under Goryeo from 1231 to 1259. There were six major campaigns: 1231, 1232, 1235, 1238, 1247, 1253; between 1253 and 1258, the Mongols under Möngke Khan's general Jalairtai Qorchi launched four devastating invasions in the final successful campaign against Korea, at tremendous cost to civilian lives throughout the Korean Peninsula. The Mongols annexed the northern areas of Korean Peninsula after the invasions and incorporated them into their empire as Ssangseong Prefectures and Dongnyeong Prefectures. In March 1258, the dictator Choe Ui of the Goryeo military regime was assassinated by Kim Jun, ending the Choe military dictatorship of Korea; after this, scholars who had insisted on peace with Mongolia gained power. This party sent an envoy to the Mongols, and a peace treaty was contracted between the Mongol Empire and Goryeo, part of which stipulated that Korea was to accept vassaldom to the Mongol Empire. Some military officials who refused to surrender formed the Sambyeolcho Rebellion and resisted in the islands off the southern shore of the Korean Peninsula.