Leo the Great was unanimously elected Bishop of Rome on September 29, 440 AD. At the Council of Chalcedon, his famous "Tome" was a decisive contribution to the Christological controversies of the fifth century. But the Tome did not stand alone. It was written in the context of over two decades of pastoral sensitivity. This collection of sermons is the best way to let Leo himself unpack the nuances and power of Chalcedonian Christology according to one of its most influential proponents. (Introduction by Jonathan Lange)