The Fathers of the 2nd to early 5th centuries: Apostolic Fathers, Ante-Nicene Fathers and Nicene Fathers. St. Ignatius of Antioch; St. Justin Martyr; St. Irenaeus; Tertullian; St. Clement of Alexandria; St. Cyprian of Carthage; Origen. Trinitarian Controversy. St. Athanasius of Alexandria; St. Basil of Caesarea; St. Gregory of Nazianzus; St. Gregory of Nyssa; St. John Chrysostom; St. Hilary of Poitiers; St. Ambrose of Milan; St. Jerome; St. Augustine of Hippo.