Oyama does not deny the possibility of the existence of Umayatoo, a powerful member of the Imperial family, who might have lived in the Ikaruga no Miya palace and also might have constructed Ikaruga-dera Temple during the Asuka period.
大山は、飛鳥時代にたぶん斑鳩宮に住み斑鳩寺も建てたであろう有力王族、厩戸王の存在の可能性は否定しない。