When MINAMOTO no Yoritomo established the military government in Kamakura, Yoritomo allowed those who had been credited for their distinguished services among the Seiwa-Genji the permission to use the Minamoto family name, but he prohibited other Genji clans from using the name at formal occasions.
源頼朝が鎌倉に武家政権を打ち立てると、頼朝は清和源氏一族内で、特に功績を認めた者だけに源姓を名乗ることを許可し、他の源氏一族が公式の場で源姓を名乗ることを禁じた。