After a series of Mongol invasions of Korea between 1231 and 1281, Goryeo signed a treaty in favor of the Mongols and became a vassal state. Kublai was declared Khagan of the Mongol Empire in 1260 although that was not widely recognized by the Mongols in the west and established his capital at Khanbaliq (within modern Beijing) in 1264. Japan was then ruled by the Shikken (shogunate regents) of the Hōjō clan, who had intermarried with and wrested control from Minamoto no Yoriie, shōgun of the Kamakura shogunate, after his death in 1203. The Mongols also made attempts to subjugate the native peoples of Sakhalin, the Ainu and Nivkh peoples, from 1264 to 1308.