An Anatolian church father: Gregory of Nazianzus

This thesis besides studying the doctrine of Trinity in accordance with the thoughts and the life of Gregory of Nazianzus also enlightens the fourth century. Because in this century, Christianity had an intense interaction with Greek philosophy and culture and produced essential elements of a theology like expressions of faith, doctrines and terminology. During this influential period the final shape of the Trinity was constituted. Gregory played an important role in the formation of this faith and especially including the Holy Spirit into the Trinity. He was a ring of the chain which carried the Nicene principles to the Council of Constantinople. He defended the orthodox Christian principles against the heretics like Apollinarius and Eunomius during his two year residence in Constantinople. Gregory who was the bishop of Constantinople and presided over the council for a short period had prepared a strong ground for decisions of the council that declared the classical Christian principles which came to us. Although he is important for both Western and Eastern Christianity he has more affected Eastern Christianity. He found basis for Orthodox thought with his mystical theology, his tendency to ascetic life and his imagery and apophatic style. He was called among the important literary figures of Byzantine too. In a word, he enlightened the important period of Christian history, i.e. fourth century with his thoughts and life and laid the groundwork for fifth century discussion points.