The Mizuno of Mikawa province were descended from Minamoto Mitsumasa, a younger brother of Minamoto Mitsunaka. Mitsumasa's descendant Shigefusa settled in Owari province, where the family would remain for many years. Shigefusa's son Shigekiyo assisted Minamoto Yoritomo in the Gempei War (1180-85) and would afterwards be moved to Mizuno in Owari. Shigekiyo's son Kiyofusa assumed the name Mizuno. During the sengoku period the Mizuno became involved in the often convoluted power struggle on the Tokai Coast, at various points supporting the Imagawa, Matsudaira, and the Oda. They became a Tokugawa retainer family after 1560, only to later serve the Toyotomi. After the Battle of Sekigahara (1600) they were made daimyô by the Tokugawa.