As the history books written during the Heian period including "Nihon Sandai Jitsuroku" (Veritable Records of Three Reigns of Japan), "Okagami" (The Great Mirror), "Todaiji Yoroku" (The Digest Record of Todai-ji Temple), and "Mizukagami" (The Water Mirror) all describe 'Shotoku Taishi' and do not use 'Umayado' and 'Toyotomimi,' it is considered the name 'Shotoku Taishi' was prevalent in this period.
平安時代に成立した史書である『日本三代実録』『大鏡』『東大寺要録』『水鏡』等はいずれも「聖徳太子」と記載され、「厩戸」「豐聰耳」などの表記は見えないため、遅くともこの時期にはすでに「聖徳太子」の名が広く用いられていたことが伺える。