When Emperor Heizei was stricken by disease in April, 809, he decided to abdicate the throne to keep out of harm's way because he thought the ghosts of Imperial Prince Sawara and Imperial Prince Iyo had caused his sickness.
809年4月、平城天皇は発病し、病を早良親王や伊予親王の亡霊によるものと考えた天皇は禍を避けるために譲位を決意する。