Saint Leo the Great

Saint Leo I was pope from 440 to 461, preacher, administrator, and Doctor of the Church. His Tome to Flavian helped shape the Council of Chalcedon’s confession that Christ is one person in two natures, divine and human. Leo’s sermons present the mysteries of Christ as realities in which Christians participate through liturgy and moral life. He also strengthened the Roman see’s pastoral and doctrinal authority during a period of political instability.