Church Fathers were writers known for their piety, orthodoxy, acceptance and antiquity. These are four of the Greek Church Fathers of the fourth century. Saints Basil the Great, John Chrysostom and Gregory of Nazianzus were the three Cappadocian Fathers or the 3 Holy Hierarchs. Athanasius was added to balance the 4 Western Fathers.
St. Athanasius was Bishop of Alexandria from 328. He became known as the Father of Orthodoxy. He wrote a "Contra Gentes" and "Oratio de Incarnatione" between 318 and 323, which St. Jerome refers to together as "Adversum Gentes Duo Libri." Athanasius opposed the Arians, and was involved in the council of Nicaea and the formulation of the Nicene Creed. Athanasius wrote the first list of the 27 books recognized by Christians as the Bible.
John Chrysostom was known for his eloquence; hence, his name Chrysostom (golden mouth). John was born at Antioch, the second city of the Eastern half of the Roman Empire. John became bishop in Constantinople, but his preaching against corruption led to his exile.
Basil was born in Caesarea of Cappadocia and went to school with Gregory of Nazianzus and the future emperor Julian the Apostate. He toured the monasteries in Egypt and then founded a monastic settlement near his home with emphasis on the communal life. He wrote "Longer Rules" and "Shorter Rules" for monastic life. Basil sold his family's holdings to buy food for the poor. Basil became Bishop of Caesarea in 370, at a time when an Arian emperor, Valens, was ruling.
Gregory persuasively preached his "Five Theological Orations" on the Trinity and defending the divinity of Christ (against the Arian position) in Constantinople, in 379. The next year Gregory was made Bishop of Constantinople. Presiding at the Council of Constantinople in 381, the Nicaean Council's position was confirmed. He then resigned and went into retirement. Gregory is also known as Gregory Nazianzen.