Mogami clan
Following the destruction of the Northern Fujiwara clan by the forces of the Kamakura shogunate in 1189, many Fujiwara partisans fled to the mountains of Dewa and continued to resist central authority. The area was divided into numerous shōen during the Kamakura period, which developed into the centers of numerous rival samurai clans. In 1335, Shiba Kaneyori received the Dewa Province as a fief from Ashikaga Takauji, but ruled it only in name. By the end of the Sengoku period, the Mogami clan had emerged as the strongest local force in the southern portion of the province, whereas the Akita clan dominated the northern portion of the province. Both clans sided with Tokugawa Ieyasu at the Battle of Sekigahara, and were thus secured in their holdings at the start of the Tokugawa shogunate.