Minamoto no Yoshitomo
At that time, the Taira, under Taira no Kiyomori, had consolidated their power in Kyoto, the capital, and expelled the Minamoto clan, their rival. Minamoto no Yoshitomo, the head of the clan, was executed, while his sons who were not executed were exiled or ordered into monasteries. The cloistered emperor, Emperor Go-Shirakawa, as well as his son, the emperor at that time (who was a puppet), Emperor Nijō, were also in Kyoto. Minamoto no Yoritomo, Yoshitomo's heir, was exiled to Izu, which was where the Hōjō domains were. (His other brothers, Minamoto no Yoshitsune and Minamoto no Noriyori were ordered into monasteries near Kyoto).