In the fifth lunar month of 1221, the Retired Emperor Go-Toba decided on lines of succession, without consulting the shogunate. He then invited a great number of potential allies from amongst the eastern warriors of Kyoto to a great festival, thus revealing the loyalties of those who rejected the invitation. One important officer revealed his loyalty to the shogunate by doing so, and was killed. Several days later, the Imperial Court declared Hōjō Yoshitoki, the regent and representative of the shogunate, to be an outlaw, and three days later the entirety of eastern Japan had officially risen in rebellion.