Sambyeolcho left Ganghwa Island, carrying commoners, soldiers and commodities on more than one thousand ships. The government organized a combined Goryeo-Mongol force to go after Sambyeolcho. Sambyeolcho moved its base to the island of Jindo, built a fortress, palace and government offices. It enthroned a new king and stood up against the Goryeo kingdom.
Sambyeolcho seized the southern coastal area and expanded its forces to Jeolla and Gyeongsang provinces as well. The people there willingly offered them supplies and supported them. Sambyeolcho fought against the combined forces of Goryeo and the Mongols for three years, but were forced to move their base to Jeju Island. Sambyeolcho held out on Jeju Island for one year, determined to drive back the Mongol army, but finally met its end on the island.