According to "Horyakukanki" (A History Book of the 14 century in Japan), Yoritsuna gave Sadatoki a slanderous account of Mumekage Adachi, a son of Yasumori, saying that he was claiming himself as an illegitimate child of MINAMOTO no Yoritomo and changed his family name to the Minamoto clan to become shogun by raising a rebellion.
『保暦間記』によると、頼綱は泰盛の子安達宗景が源頼朝の落胤であると称して源氏に改姓し、謀反を起こして将軍になろうとしている、と貞時に讒言したという。