Avitus decided to react. First he chose Messianus, one of his collaborators in his embassy to the Visigoths ordered by Petronius Maximus, as the new "magister militum"; then he probably went to Gaul (Hydatius says to Arelate) to collect all the available forces, probably the Visigoth guard he had just disbanded; finally he led his forces against the troops of Ricimer, near Piacenza. The Emperor and his army entered the city and attacked the huge army led by Ricimer, but after a great massacre of his men, including Messianus, Avitus fled on 17 or 18 October 456. In the immediate aftermath Ricimer spared his life, but forced him to become Bishop of Piacenza.