Sambyeolcho Resistance
Rejecting the return to Gaegyeong, the Sambyeolcho under Bae Jung-son rose on Ganghwa and, moving to Jindo and then Jeju, held out for three years against combined Goryeo and Mongol forces.
Chipmunkdavis · CC BY-SA 4.0 · Source
The Sambyeolcho had been the military backbone of the Choe regime. In the sixth month of 1270 Bae Jung-son made the royal kinsman Wang On king and sailed with over a thousand ships to Jindo, where he built Yongjangseong and controlled the southern coast; a letter to Japan presented them as the government of Goryeo.
When Goryeo-Mongol forces took Jindo in the fifth month of 1271 and Bae fell, Kim Tong-jeong led the survivors to Jeju and fought on from Hangpaduri. Jeju fell in the fourth month of 1273, and the Yuan set up the Tamna Commandery there. The resistance is seen as an expression of defiance against the Mongols.