Gregory of Nazianzus One of the Cappadocian fathers, Gregory of Nazianzus (c.330–389), given the title, “The Theologian,” was instrumental in the development of the doctrine of the Trinity, specifically the distinct terms to describe the Persons of the Godhead (Unbegotten, eternally begotten, and procession). Gregory’s main contribution to the development of Christology was in his opposition to Apollinarius. He argued that when Adam fell, all of humanity fell in him; therefore, that fallen nature must be fully united to the Son—body, soul, and mind; ‘for the unassumed is the unhealed’. Gregory’s Doctrine of the Trinity His clearest statement on the Trinity is found in his Oration 25.15–18. Oration 25 is part of a series of sermons delivered in 380. As a gesture of gratitude, Gregory dedicates Oration 25 to Christian philosopher Maximus the Cynic, as a sort of ‘charge’ for him to push forward and remain strong in the orthodox teachings of the faith. And these sections ar...