Minamoto no Sonetomo (1192-1219) became shogun at the age of twelve in 1204, when his brother Yoriie was murdered. He lived in Kamakura, was promoted to the office of Udaijin, a high imperial rank, and wrote much fine verse until he was assassinated by accomplices of the Hojo family, who hoped thereby to end the hegemony of the Minamoto family and consolidate their power.