According to "Kokon chomon ju" (A collection of Tales Heard, Past and Present) in the middle of the thirteenth century, Yokohagi Dainagon was described as FUJIWARA no Toyonari and after that, the father's name had been established as Udaijin (minister of the right) FUJIWARA no Toyonari and the daughter's name had been as Chujo Hime.
13世紀半ばの『古今著聞集』（ここんちょもんじゅう）ではヨコハギ大納言の名は藤原豊成とされており、以降、父の名は右大臣藤原豊成、娘の名は中将姫として定着していく。