Toshinori UNE proposes the theory that Emperor Kanmu changed family names of the clans based on a policy different from that in the past, and therefore the order of clans in the Kizoku society changed drastically, generating a new Kizoku society order with the Minamoto clan, the Taira clan, the Fujiwara clan, and the Tachibana clan at its pinnacle.
宇根俊範は、桓武天皇は従来と異なる方針で諸氏族の改賜姓を行い、このため貴族社会における各氏族の序列が大きく変化し、源平藤橘を頂点とする新たな貴族社会秩序が生じたとする。