In the eleventh and twelfth centuries, many families were formed with the establishment of castles; the names of the families that formed during this period were derived from their territorial lands or castles.
11・12世紀ごろには城塞の建設に伴っての家門形成が顕著であり、このころ形成された多くの家門の名が支配地や城塞を起源としている。