Princess Iitoyo was not officially stated as Emperor as she was called the daughter of Emperor Richu in the Kojiki (Records of Ancient Matters), and was called the daughter of Prince Ichinobe no Oshihano in Nihon shoki (Chronicles of Japan), however she was called 'the twenty fourth Emperor Iitoyo' in Fusoryakki (A Brief History of Japan), and there were some of the opinion that she should be considered as Emperor.
※飯豊皇女は、古事記では履中天皇の娘、日本書紀では市辺押磐皇子の娘であるため公式には天皇とされていないが、扶桑略記に「第24代飯豊天皇」とあるため、天皇として扱うべきとの意見もある。