After the Imperial Prince Munetaka, the second son of the Emperor Gosaga, retired from the list of the sixth Kamakura Shogun, Imperial Prince Koreyasu, the eldest son of the Imperial Prince Munetaka, became the seventh Shogun and was given the surname of Minamoto, to call himself MINAMOTO no Koreyasu.
後嵯峨天皇の第二皇子宗尊親王が第6代鎌倉将軍一覧を退いた後、その一男で7代将軍に就任した惟康親王に対し、源姓が賜与されて「源惟康」となった。