Leo possessed those qualifications which made him the master spirit of his age and the "Founder of the mediæval Papacy." Lofty in his aims, severe and pure in life, of indomitable courage and perseverance, inspired by a fanatical belief in the Petrine theory, uncompromisingly orthodox, the great first theologian in the Roman Chair, he made the first clear-cut exposition of the extreme limits and prerogatives of the mediæval Papacy.[183:1] He asserted and exercised the superabounding power of the Pope to regulate every department of Church government without any human limitations. Driven on by a dream of the universal dominion of Rome and Christianity, a great orator who swayed the Romans at will, he acted as a resolute Christian monarch conscious of his divine mission. Possessed of a capacity for complex rule, an extraordinary organiser and administrator, he used all his ability to make Christianity and the Papacy the one great world power. Twice he saved Rome from the barbarians, once in 452 when Attila, King of the Huns, was persuaded to withdraw without attacking the city, and again in 455 when the Vandal leader, Genseric, was induced to spare the capital from fire and murder. He drove heresy out of Italy and suppressed it in Spain. He forced the African Christians to submit to his authority (443), regained the papal power lost in East Illyria, compelled the Gallic bishops to obey his mandates,[184:1] and even asserted his supremacy over the Eastern Church. Through a legate he presided over the fourth ecumenical Council of Chalcedon, guided its theological discussions, and was "the finisher of the true doctrine of the presence of Christ." Pope Leo laid the greatest possible emphasis upon the fact that there is one God, one Church, one universal bishop, one faith, and one interpreter of that faith, and that the recognition of this basic fact alone could bring unity and efficiency to Christendom. He very wisely cultivated a close alliance with the state and secured from Valentinian III. the promulgation of an imperial edict in 445, which raised him to the exalted position of "spiritual director and governor" of the Universal Church. Thus the Pope would issue his laws for the Church, just as the Emperor did for the Empire. After Leo the Great, who died in 461, no important Pope filled the Chair of St. Peter until the time of Gregory I., called the Great (590-604). If Leo drew the outline of the mediæval Papacy, Gregory made it a living power. He issued the first declaration of independence and assumed actual jurisdiction over the whole Western Church. His high ideal was completely realised so that even Gibbon calls his pontificate the most edifying period of Church history.[185:1]