He was adopted by Emperor Gomomozono, who was in critical condition, a day before he was enthroned (it has been said that Emperor Gomomozono had already died, but that wasn't verified because there was an interregnum period).
即位の前日に危篤の後桃園天皇の養子になる（実際にはすでに後桃園天皇は崩御しており、空位をさけるために発表されていなかったという）。