Gregory of Nazianzus was a fourth-century Cappadocian Father who for a short tenure served as Bishop of Constantinople and was already being cited as an authority at church councils in the century after his death. However, before he became known as Saint Gregory the Theologian, Gregory was an accomplished poet and an Athenian-trained teacher of Classical Greek literature. As such he learned to produce orations for public festivals within the ripe literary tradition of Classical epideictic rhetoric, and in his orations for Christian festivals his performance of theology is informed by a long-standing association in Greek literature between festivals and the performance of philosophy. This book shows how Gregory's  orations for Christian festivals such as Christmas and Easter represent a crucial point in the reception and transformation of Mediterranean festival culture, rhetorical theory, Platonism, and Imperial Greek oratory, and how his vision of festival rhetoric would in turn influence Byzantine homilists, hymnographers, and theologians for centuries to come.