Between 1253 and 1258, the Mongols under Jalairtai launched four devastating invasions in the final successful campaign against Korea. Möngke realized that the hostage was not the blood prince of the Goryeo Dynasty. So Möngke blamed the Goryeo court for deceiving him and killing the family of Lee Hyeong, who was a pro-Mongol Korean general. Möngke' commander Jalairtai devastated much of Goryeo and took 206,800 captives in 1254. Famine and despair forced peasants to surrender to the Mongols. They established a chiliarchy office at Yonghung with local officials. Ordering defectors to build ships, the Mongols began attacking the coastal islands from 1255 onward. In the Liaodong Peninsula, the Mongols eventually massed Korean defectors into a colony of 5,000 households. In 1258, Goryeo's King Gojong and one of the retainers of the Choe clan, Kim Injoon, staged a counter-coup and assassinated the head of the Choe family, ending the rule of the Choe family which spanned six decades. Afterwards, the king sued for peace with the Mongols. When the Goryeo court sent the future king Wonjong as hostage to the Mongol court and promised to return to Kaegyong, the Mongols withdrew from Central Korea.