He had become one of Italy's most prominent socialists. In September 1911, Mussolini participated in a riot, led by socialists, against the Italian war in Libya. He bitterly denounced Italy's "imperialist war", an action that earned him a five-month jail term. After his release, he helped expel Ivanoe Bonomi and Leonida Bissolati from the Socialist Party, as they were two "revisionists" who had supported the war.