保元之亂
With the outbreak of the Hōgen Rebellion in 1156, the members of the Minamoto and Taira samurai clans were beckoned into the conflict. Yoshitomo sided along with Taira no Kiyomori in support of the Emperor Go-Shirakawa and Fujiwara no Tadamichi, while his father Minamoto no Tameyoshi sided with the retired Emperor Sutoku and Fujiwara no Yorinaga. Yoshitomo, defeating his father and the forces of Sutoku and Yorinaga, became head of the Minamoto and established himself as a political power in the capital of Kyoto. However, despite his attempts to have his father pardoned, Tameyoshi was executed. Also, the outcome of the Hōgen rebellion established the Minamoto and Taira as the two strongest political rivals in the country.