Fumihiko GOMI suggested that the concept of 'Family,' which was gradually being formed in the late Heian, the period of the rule of a cloistered emperor, began to spread among the court nobles' society in Kyoto, forming house status and fixing family business and trade.
平安時代の後期、院政期頃にすこしづつ形を成してきた所謂「イエ」の概念が、更に家格の形成、家業・家職の固定化として京の公家社会から進んでいったことを五味文彦は示唆している。