For the further development of the spiritual authority of Rome two things were necessary—tact and imperial support. Bishop Zosimus possessed neither, and his brief pontificate did as much as could be done within two short years to injure the prestige of the apostolic seat. He was smitten on one cheek by the synods of Africa, he was smitten on the other by the Gallic bishops at the Council of Turin.[52] He intervened in the Pelagian controversy, and was obliged to eat his own words. But his inglorious pontificate remains a landmark,[53] because he was the first to make a strenuous attempt to exercise sovran rights which the western churches had never admitted or been asked to admit—rights which a more competent pontiff afterwards secured. The indiscretions of Zosimus were atoned for by more moderate successors, but the most consummate tact and adroitness would never have won the powers of intervention which he had claimed and the Gallic bishops had repudiated, if Pope Leo had not gained the ear of the Emperor. In A.D. 445, one of the greatest dates in the history of the growth of the papal power, the Emperor Valentinian III. conferred on the Bishop of Rome sovran authority in the western provinces which were still under imperial sway.[54] But in the meantime, though southern Gaul might resist Zosimus and disregard Celestine when they attempted to assert a right of control, though Celestine might discern in the power of the see of Arles and in the tendencies of the monks of Lérins forces adverse to Roman influence, no Gallic bishop would have thought of questioning the appellate jurisdiction or the moral authority of the Roman see, as exercised before the days of Zosimus. Germanus of Auxerre might sympathise with Hilary of Arles in his struggle with Pope Leo, but in dealing with heresy in Britain he had acted cordially with Pope Celestine. No one could ascribe more importance than Vincentius of Lérins to the decisions of the “apostolic seat.”[55] It would be a grave mistake to infer from the disputes which cluster round Arles that the bishops of Gaul had ceased in any way to acknowledge the older claims of Rome or to reverence it as the head of Christendom. [Sidenote: THE ROMAN SEE]