Accordingly, as a result of negotiations between Sanekane SAIONJI, Kanto moshitsugi (court-appointed liaison with the bakufu) and the regent Tokimune HOJO, Imperial Prince Hirohito (Emperor Fushimi), the son of Gofukakusa, became an adopted child of Kameyama in 1275, and was given the title of Imperial Prince and formally installed as the Imperial Prince.
このことから、関東申次西園寺実兼と執権北条時宗との折衝により、後深草の皇子熈仁親王（伏見天皇）が同年中に亀山の猶子となり親王宣下、立太子した。