The Genpei War was the culmination of a decades-long conflict between between the Taira and Minamoto clans during the late-Heian period of Japan over dominance of the Imperial court, and by extension, control of Japan. In the Hōgen Rebellion and in the Heiji Rebellion of earlier decades, the Minamoto attempted to regain control from the Taira and failed. In 1180, Taira no Kiyomori put his grandson Antoku (then only 2 years of age) on the throne after the abdication of Emperor Takakura.