It broke down after the Heian period, but Shinshu who was the great-great-grandson of Shima had Imperial Prince Kazurawara with the Emperor Kanmu and its blood line was led to Kanmu-Heishi (Taira clan).
平安時代以降は衰退したが、島の玄孫の真宗は桓武天皇との間に葛原親王をなし、桓武平氏にもその血統を伝える事となった。