According to "The Sonpi Bunmyaku" (a text compiled in the fourteenth century that records the lineage of the aristocracy), his biological father was Nakakiyo SATO who was the brother of Norikiyo SATO (Saigyo, who can be said to be a direct descendant of the FUJIWARA no Hidesato line), and he became Sanemoto GOTO's foster son.
『尊卑分脈』によると実父は藤原秀郷流の嫡流とも言える佐藤義清（西行）の兄弟、佐藤仲清で、後藤実基の養子となった。