Minamoto no Sanetomo
After Yoritomo's death in 1199, the office of shogun weakened. Behind the scenes, Yoritomo's wife Hōjō Masako became the true power behind the government. In 1203, her father, Hōjō Tokimasa, was appointed regent to the shogun, Yoritomo's son Minamoto no Sanetomo. Henceforth, the Minamoto shoguns became puppets of the Hōjō regents, who wielded actual power.