Born in 1264, son of Prince Munetaka. When his father was stripped of the shogunal title in 1266 and sent back to Kyoto on suspicion of rebellion, the three-year-old Koreyasu became the 7th shogun. His extreme youth meant the shogunate's senior officials ran all governance while Koreyasu served as a purely nominal figurehead. His long tenure of 23 years encompassed both Mongol invasions—the Battle of Bun'ei (1274) and the Battle of Koan (1281)—during which regent Hojo Tokimune bore all real decision-making for the national crisis, while Koreyasu was nominally the supreme commander. In 1289 he was deposed and returned to Kyoto, succeeded by Prince Hisaaki, son of Emperor Go-Fukakusa. He lived on until 1326, dying at 63. His extraordinary tenure—the longest of any Kamakura shogun—combined with his total lack of real authority makes him the clearest embodiment of the shogunal office's transformation into an empty title.