The Musashi clan is a descendant of MUSASHI no Fuwamaro, who is the person rendering distinguished service in the Rebellion of Emi no Oshikatsu (Previously called HASETSUKABENOATAE no Fuwamara; he was ranked Jushiinoge [Junior Fourth Rank, Lower Grade] when he died in May 7, 787), and he was Adachi gunji, as the creator of Musashi Province worshipping Hikawa-jinja Shrine.
武蔵氏は藤原仲麻呂の乱（恵美押勝の乱）の功労者武蔵不破麻呂（丈部直不破麻呂、延暦6年4月11日_(旧暦)に従四位下で没）の子孫であり、氷川神社を祀る武蔵国造家として、代々足立郡司を勤めていた。