Soga also followed the precedent set by the Katsuragi and Fujiwara clans by marrying off his daughters SOGA no Kitashihime and Oane no Kimi to Emperor Kinmei, and established himself as a maternal relative of the imperial family.
また、過去の葛城氏や後の藤原氏同様、娘蘇我堅塩媛、小姉君を欽明天皇に嫁がせることにより天皇家の外戚となっていく。