According to the Shoku-Nihongi (the second in a series of chronicles about Japan), his mother, TAKANO no Nigasa, was a descendant of the Baekje Royal Family, whose ancestors were the Baekje Muryeong-wang.
母の高野新笠は、百済の武寧王を祖先とする百済王族の末裔と続日本紀に記されている。