Notable Fathers of the Early Byzantine Period.

St. Anthony the Great († 356).

St. Anthony, commemorated January 17, is considered to be the Father of monasticism, and The Life of St. Anthony, by St. Athanasius, presents him as a truly inspiring example of monastic ascetical perfection. During the Arian controversies, he risked his life defending the Orthodox teachings of St. Athanasius in Alexandria.

St. Athanasius the Great, Patriarch of Alexandria († 373).

St. Athanasius, commemorated January 18 and May 2, was a great defender of the Orthodox faith during the Arian controversies and was exiled five times for his labors. Among his major writings are The Incarnation of Christ and The Life of St. Anthony, which serve as major inspirations for Orthodox theology and monastic spirituality.

St. Basil the Great, Archbishop of Caesarea in Cappadocia († 379).

St. Basil, commemorated January 1 and January 30, was a notable theologian and spiritual writer of the 4th Century and is noted for his many writings on numerous theological and spiritual subjects, as well as commentaries on Holy Scripture. During the Sundays of Great Lent, as well as on his Feast Day (Jan. 1), the Liturgy of St. Basil the Great is served, although probably only the prayers are actually of this Saint.

St. Cyril, Patriarch of Alexandria († 444).

St. Cyril, commemorated on January 18 and June 9, was the leader in the defense of Orthodoxy against the Nestorians, and was a firm defender of the veneration of the Virgin Mary as Theotokos. He was especially prominent in the deliberations of the Third Ecumenical Council.

St. Ephraim the Syrian († 373-9).

St. Ephraim, commemorated January 28, was a major spiritual writer and hymnographer of the 4th Century, and is especially noted in Orthodox liturgical life for, among other things, his inspiring work, The Lenten Prayer of St. Ephraim the Syrian, which is said at all of the weekday services of Great Lent.

St. Gregory the Theologian, Archbishop of Constantinople († 389).

St. Gregory, commemorated January 25 and 30, was a fellow student and friend of St. Basil the Great and was a leading opponent of the Arians. He has been honored by the Church with the title “Theologian,” being one of only three, so honored (the others being St. John the Evangelist, and St. Simeon the New Theologian), primarily because of his Five Theological Orations.

St. Gregory, Bishop of Nyssa (4th Cent.).

St. Gregory was the younger brother of St. Basil the Great and is commemorated on January 10. He is especially known for his spiritual writings, as well as various dogmatic works, including his Great Catechism.

St. John Chrysostom, Archbishop of Constantinople († 407).

St. John Chrysostom (the Golden-mouth), commemorated January 27 and 30 and November 13, was one of the greatest preachers of his time (late 4th Century) and was known for his zeal for Orthodoxy and his passionate defense of the poor, boldly exposing the vices of his age, for which reason he was eventually deposed and exiled. The bulk of his works are sermons on Holy Scripture, especially the Epistles of St. Paul, as well as other ascetical and pastoral works, including his On the Priesthood. To St. John is attributed the usual Divine Liturgy, although, as in the case of that of St. Basil the Great, probably only certain prayers are properly his.