The family was descended from MINAMOTO no Mareyoshi, the fifth son of MINAMOTO no Yoshitomo who was the leader of the Kawachi-Genji (Minamoto clan), a family line of the Seiwa-Genji (Minamoto clan), and a younger maternal half-brother of MINAMOTO no Yoritomo.
家系は清和源氏の一家系河内源氏の棟梁源義朝の五男にて、源頼朝の同母弟源希義を祖とする。