Leo the Great
BIOGRAPHY
Leo the Great served as Bishop of Rome from September 29, 440, until his death. He was the first of three popes honored with the title “the Great” in the Annuario Pontificio, alongside Gregory I and Nicholas I.
A Roman aristocrat by birth, Leo is perhaps best known for his historic meeting with Attila the Hun in 452, during which he successfully persuaded Attila to abandon his invasion of Italy. Theologically, he is remembered as a Doctor of the Church, particularly for his Tome of Leo, a pivotal document in the Christological debates of the Council of Chalcedon (451). This council defined the doctrine of the hypostatic union, affirming that Christ possesses both divine and human natures, united in one person “without confusion or division.” The council's rulings led to significant theological disputes, including the schism involving Monophysitism, Miaphysitism, and Dyophysitism.
Leo also played a crucial role in shaping the doctrine of papal authority, strengthening the primacy of the Bishop of Rome within the Church.