8. Interference in the most vital concerns of the Church was recognised as an imperial prerogative. The Emperor called the Council, presided over its proceedings, acted as mediator between contending factions, forced the Nicene Creed on the Church, fixed the day for celebrating Easter, and approved the first ecclesiastical canons. 9. The various heresies and schisms of the time were condemned. This action threw into prominent relief throughout the Empire the powerful party of orthodox Catholics, who henceforth were to control the destinies of the Church in both its internal and external organisation and evolution. The condemnation of Arianism was only a temporary victory. Soon Constantine himself was won over by the Arians, invited Arius to his court, and ordered Athanasius, who meanwhile had become Bishop of Alexandria (328), to reinstate Arius in his parish. Athanasius refused to do so, and was condemned and deposed by the councils of Tyre (334) and of Constantinople (335), and exiled by the Emperor to Treves in Gaul. Arius died before he could be recalled (336). Constantine II. restored Athanasius to his see (338), but his brother Constantius and his Arian friends deposed him again (339). Athanasius then fled to Pope Julius at Rome (339), who laid his case before a Western council (341) which vindicated both his creed and his rights. This supreme appellate power assumed by the Bishop of Rome is significantly prophetic. To heal the Arian conflict, which was again active--this time between the East and the West,--the Council of Sardica was called in 343. The Roman party controlled it, reconfirmed the Nicene Creed, and adopted twelve new canons. The Arians refused to take part and held a rump council. The result was a wider separation of the East and the West.[144:1] Under Constantius, however, the Arian party grew stronger, held the three Arian councils of Sirmium (351), Arles (353), and Milan (355), forced their decrees upon the whole Church, exiled Hosius, Hilary, and Lucifer, drove Athanasius, who had meanwhile once more returned to his office (346), out of his see, and even deposed Pope Liberius[145:1] and elected an Arian Pope, Felix II., in his place. Thus the Arian party seemed triumphant East and West.