The shogun's nephew killed him on the shrine steps in 1219 to avenge his father, and the Minamoto line of shoguns ended that night

Minamoto no Yoritomo founded the Kamakura shogunate and died in 1199. His elder son Yoriie inherited the house and became shogun, but his mother's family, the Hōjō, limited his powers through a council. Yoriie plotted with the Hiki family against the Hōjō, failed, and was confined at Shuzenji in Izu, where he was killed in 1204. His younger brother Sanetomo had become shogun in 1203 at 11. Real power stayed with his mother, Hōjō Masako, and her brother, the regent Hōjō Yoshitoki. Sanetomo wrote poetry, studied under Fujiwara no Teika and once ordered a ship built to sail to Song China; it failed to float. In 1218 the court raised him in quick steps to Minister of the Right. When an adviser warned against it, Sanetomo answered, as the Sekai Daihyakka records, that the Minamoto main line would die out and he wanted at least to raise the family name. Yoriie's son Kugyō, head priest of Tsurugaoka Hachimangū, believed Sanetomo was his father's enemy. On the 27th day of the 1st month of 1219, at the shrine ceremony for his new office, Kugyō stabbed Sanetomo to death. Kugyō went to the Miura family for help to become shogun and was killed by Miura Yoshimura's men. Historians still debate whether Yoshitoki or Yoshimura was behind him. More than 100 vassals took the tonsure. The Hōjō brought an infant from the Fujiwara regents' house, a distant relative of Yoritomo, to be the next shogun.