defining orthodoxy versus heterodoxy and heresy. In the Eastern Roman empire, known as Byzantium, the Arian controversy began with its debate of Trinitarian formulas which lasted 56 years. As it moved into the West, the center of the controversy was the "champion of orthodoxy", Athanasius. In 355 Constantius, who supported Arianism, ordered the suppression and exile of Athanasius, expelled the orthodox Pope Liberius from Rome, and exiled bishops who refused to assent to Athanasius's exile. In 355, Dionysius, bishop of Mediolanum (Milan) was expelled from his episcopal see and replaced by the Arian Christian Auxentius of Milan. When Constantius returned to Rome in 357, he consented to allow the return of Liberius to the papacy; the Arian Pope Felix II, who had replaced him, was then driven out along with his followers. The last emperor of the Constantinian dynasty, Constantine's half-brother's son Julian () opposed Christianity and sought to restore traditional religion, though he did not arrange a general or official persecution. Valentinianic–Theodosian period According to the Collectio Avellana, on the death of Pope Liberius in 366, Damasus, assisted by hired gangs of "charioteers" and men "from the arena", broke into the Basilica Julia to violently prevent the election of Pope Ursicinus. The battle lasted three days, "with great slaughter of the faithful" and a week later Damasus seized the Lateran Basilica, had himself ordained as Pope Damasus I, and compelled the praefectus urbi Viventius and the praefectus annonae to exile Ursicinus. Damasus then had seven Christian priests arrested and awaiting banishment, but they escaped and "gravediggers" and minor clergy joined another mob of hippodrome and amphitheatre men assembled by the pope to attack the Liberian Basilica, where Ursacinus's loyalists had taken refuge. According to Ammianus Marcellinus, on 26 October, the pope's mob killed 137 people in the church in just one day, and many more died subsequently. The Roman public frequently enjoined the emperor Valentinian the Great to remove Damasus from the throne of Saint Peter, calling him a murderer for having waged a "filthy war" against the Christians. In the 4th century, the Terving king Athanaric in ordered the Gothic persecution of Christians. Athanaric was perturbed by the spread of Gothic Christianity among his followers, and feared for the displacement of Gothic paganism. It was not until the later 4th century reigns of the augusti Gratian (), Valentinian II (), and Theodosius I () that Christianity would become