Chiba clan
During the Genpei War (1180–1185) the Chiba clan, as well as the Hōjō, Miura, and Doi clans, opposed the greater 'core' Taira clan and supported Minamoto no Yoritomo. Chiba Tsunetane, clan chief of the period, won Yoritomo’s trust and helped establish the Kamakura shogunate. The power of the clan increased in this period, but ultimately declined during the Muromachi period (1336–1573).