Pope Leo was one of the great bastions of Orthodoxy during the time of the monophysite heresy and its offshoots. 'According to some, this Saint was born in Rome, but according to others in Tyrrenia (Tuscany), and was consecrated to the archiepiscopal throne of Rome in 440. In 448, when St Flavian, Archbishop of Constantinople [also commemorated today], summoned Eutyches, an archimandrite in Constantinople, to give account for his teaching that there was only one nature in Christ after the Incarnation, Eutyches appealed to St Leo in Rome. After St Leo had carefully examined Eutyches' teachings, he wrote an epistle to St Flavian, setting forth the Orthodox teaching of the person of Christ, and His two natures, and also counseling Flavian that, should Eutyches sincerely repent of his error, he should be received back with all good will. At the Council held in Ephesus in 449, which was presided over by Dioscorus, Patriarch of Alexandria (and which Saint Leo, in a letter to the holy Empress