Musashi Province, a province of ancient Japan, was comprised of the present-day prefecture of Tokyo as well as parts of Saitama Prefecture and Kanagawa Prefecture. It was the largest province in the Kantou and was formed in the 7th century. It was governed by many, many clans, including the original Houjou Clan for about 100 years starting from the 1210s. The Later Houjou Clan took the territory in the late Sengoku Era after the Battle of Kawagoe Castle in 1546 drove out the Uesugi influence. Tokugawa Ieyasu took control of the Kantou after the fall of the Houjou Clan in 1590.