In 364, Hilary extended his efforts once more beyond Gaul. He impeached Auxentius, bishop of Milan, a man high in the imperial favour, as heterodox. Emperor Valentinian I accordingly summoned Hilary to Milan to there maintain his charges. However, the supposed heretic gave satisfactory answers to all the questions proposed. Hilary denounced Auxentius as a hypocrite as he himself was ignominiously expelled from Milan. Upon returning home, Hilary in 365, published the "Contra Arianos vel Auxentium Mediolanensem liber," describing his unsuccessful efforts against Auxentius. He also (but perhaps at a somewhat earlier date) published the "Contra Constantium Augustum liber", accusing the lately deceased emperor as having been the Antichrist, a rebel against God, "a tyrant whose sole object had been to make a gift to the devil of that world for which Christ had suffered."