In "A Record of Ancient Matter" and "Chronicles of Japan" she was not regarded as Emperor, but in "Fuso Ryakki" (A Brief History of Japan) she was described as 'Emperor Iitoyo the fourth Empress,' in Honcho koin jounroku (the Emperor's family tree, made in the Muromachi period) as 'Iitoyo Emperor Oshinumibe princess,' and additionally in the apocryphal book "Sendai Kujihongi taiseikyo," there was even shigo (posthumous title) 'Emperor Seitei,' where she was treated as Emperor.
記紀では天皇として認められていないが、後世の史書である『扶桑略記』に「飯豊天皇廿四代女帝」、『本朝皇胤紹運録』に「飯豊天皇忍海部女王是也」と記される上、偽書の『先代旧事本紀大成経』には「清貞天皇（せいていてんのう）」の諡号まであり、天皇の扱いとなっている。