There are several theories about his place of birth, and it is said that it was Okawara, Shinano Province (present-day Oshika-mura, Nagano Prefecture), where his father, Imperial Prince Muneyoshi, maintained a foothold for many years, or Iinoya, Totomi Province (present-day Iinoya, Inasa-cho, Hamamatsu City, Shizuoka Prefecture), where his father stayed for a while after being washed up on the shore of Enshu, and following that, there are several theories about his mother, assuming her to be a woman of the Chiku clan, or a daughter of Michimasa II (ancestor of Naomasa II, a senior vassal of Ieyaku TOKUGAWA).
出生地については諸説あり、父宗良親王が長年拠点とした信濃国大河原（現、長野県大鹿村）や、遠州に漂着後しばらく滞在した遠江国井伊谷（現、静岡県浜松市引佐町井伊谷）であったとされ、それに付随して母も知久氏の女や井伊道政（徳川家康の重臣井伊直政の祖）の娘と諸説ある。