In 355, Emperor Constantius II, who was sympathetic towards the Arians, banished Liberius for refusing to subscribe to a sentence of condemnation against Saint Athanasius, staunch opponent of Arius of Alexandria.
The Collectio Avellana says that Damasus was a deacon in Rome;[2] Alban Butler and the Encyclopedia Britannica name him an archdeacon of the Roman Church.
Having sworn to have no Pope but Liberius, members of the Roman clergy then chose the Archdeacon Felix as his successor, an action that proved unpopular with the general populace.
Apparently the Emperor expected Felix and Liberius to rule jointly, but when Liberius returned, Felix was forced to retire to Porto, near Rome, where, after making an unsuccessful attempt to establish himself again in Rome, he died on 22 November 365.
Such was the violence and bloodshed that the two praefecti of the city were called in to restore order, and after a first setback, when they were driven to the suburbs and a massacre of 137 was perpetrated in the basilica of Sicininus (as cited in Ammianus Marcellinus), the prefects banished Ursicinus to Gaul.