This clan originated with the descendents of Prince Masamochi, Prince Yukitada, and Prince Koretoki (all of whom were grandsons of Emperor Ninmyo), who were given the honorary surname of Taira no Ason upon being demoted from the Imperial family.
仁明天皇の孫・雅望王、行忠王及び惟時王の子孫が平朝臣を賜姓されて臣籍に下ることによって成立した氏族。