In 1268 Emperor Kameyama's Prince, Imperial Prince Yohito, became Crown Prince at the request of Retired Emperor Gosaga, although there was another possible successor to the throne, Gofukakusa in's Prince, Hirohito who was older than he.
文永五年（1268年）に、後嵯峨上皇の指示により、年長の後深草院皇子熈仁を差し置いて亀山皇子世仁親王が立太子した。