The Fathers of the Church can be roughly divided into certain time periods, but it important to establish, first, what it means to be a Father of the Church. The four necessary criteria are orthodoxy of faith, holiness of life, Church approval, and antiquity, as basically defined by St. Vincent, himself an eventual Church Father.
Orthodoxy of faith certainly does not mean that each Father had to get everything right or be discounted. The early Church was in a time of rapid learning and reflection, and certainly there were disputes even between what are now considered the Fathers. Origin, for example, even took much of his allegorical interpretation too far in some areas, but his vast and great speculative writing still win him a place among the Fathers. As to holiness of life, one can immediately recognize that certain Fathers are not canonized saints, and canonization is certainly not a prerequisite to be considered a Father. Again, we might mention Origin, Tertullian, and others. Still, a general holiness of life spent trying to be conformed to the will of God is recognized in those titled “Father of the Church.”
Church approval is a rather straight forward criteria, as it is the Church that has determined the list (or lists) of Fathers. Their teaching and writings have become part of the living tradition of the Church. As to antiquity, we see that St. Vincent himself was eventually called a Father, even as he probably considered “antiquity” to have ended before his own time. Generally the Patristic era begins with the Apostolic Fathers and ends with the seventh or eighth century.
To the Apostolic Fathers belong those “Christian writers of the first and second centuries who are known, or are considered, to have had personal relations with some of the Apostles, or to have been so influenced by them that their writings may be held as echoes of genuine Apostolic teaching.” Most of these Fathers were bishops, and some became martyrs. It took almost no time in the early church for heresies to develop (we even see Paul writing against them in some of the New Testament epistles). Much of the teaching of the Apostolic Fathers is on what it means to be a Christian, what it means to live in a world that is, for the most part, Pagan, and how to stand fast in the faith against persecution. Among the great Fathers of this period are St. Clement of Rome, St. Ignatius of Antioch, and St. Polycarp of Smyrna.
Apologetics means, broadly speaking, a form of apology. An apologist basically fulfills the command of the First Epistle of St. Peter, to “be ready always to give an answer to every man that asketh you a reason of the hope that is in you.” St. Justin Martyr and St. Irenaeus of Lyons are two of the first Apologists, who offered defenses of the faith of the Catholic Church against the background of the culture and philosophy of the time.
Whether it was pagan thought or Gnosticism, for example, the apologists’ writings focused on a rational vindication of Catholic belief and practice.
St. Justin Martyr, for example, was a philosopher who searched many philosophical traditions for the truth, until he came to rest in the peace of the Gospel of Christ. He used his knowledge of various philosophies to defend the faith in dialogues with both the Pagans and the Jews. St. Iranaeus of Lyons wrote a large work commonly called Against the Heresies, and is an immense apologetic focused mostly on the early gnostic sects.
The third century brought us such great minds as that of Tertullian and of Origen. Here, we enter a time when the Church seemed to be making a decision (cognitively or not) about whether to establish its teachings in the language of the Hellenized culture or not. Tertullian would ask the famous question “what has Athens to do with Jerusalem?” but the majority of the Fathers seemed to move in the other direction. Philosophy, especially neoplatonic philosophy, had a well established vocabulary that proved quite useful to the Church once it started reflecting deeply on such mysteries as personhood, the dual nature of Christ, and the unity and diversity of the Trinity. Several of the recognized Fathers from this period have never been canonized, such as Novation, as well as Origin and Tertullian, already mentioned above.
The fourth century and early fifth century is the great age of the Fathers, and is considered the Golden Age, bringing us such teachers as St. Augustine, the Doctor of Grace, and St. Jerome, the great Biblical scholar and exegete of the east, as well as St. John Chrysostom, the Golden mouthed. St. Athanasius, St. Ambrose, and St. Basil the Great also belong to this era. There are, in fact, too many great names to mention here. Saints Augustine, Jerome, Ambrose, and Gregory the Great are known as the four great Western Church Fathers.
These authors wrote in a time, generally, when Catholicism was accepted and no longer persecuted in the Roman world. With greater freedom, and following the council of Nicaea, we see timeless tomes emerge on the Trinity, the unity of the Church, the two natures and one person of Christ, and reflections on the work of the Holy Spirit. Also, discussion (and often disputes) among the bishops on tough questions come to surface. With some of the focus turned away from defending the faith against those on the outside, further clarification on the Church from within is debated. Details of such issues as the relationship of grace and free will and the meaning of the Church as both the Body of Christ and as human institution can be more freely discussed after the “victory” of Christianity in the empire.
Among these Fathers in the West, Augustine of Hippo deserves special mention. St. Augustine is commonly referred to as the Doctor of Grace, as his reflections on the necessity of grace in the life of man to do anything good at all permeate his writings. His contemplation of grace as a free gift of God certainly appears in the pages of his great works such as the Confessions, The City of God, and the Trinity, and is clearly brought out in his polemic against the Pelagian heresy. This issue and its resolution (although the mystery of grace and free will is likely to never to be resolved this side of the grave) in St. Augustine is defining for the western Church.
Augustine is cited almost constantly by all sides in many debates, such as that between the protestant reformers and the Catholic Church. His authoritative standing is unquestioned among almost all Christians. St. Augustine is only rivaled in Catholic thought, outside the Biblical authors themselves, by St. Thomas Aquinas. Among our separated brethren, however, Augustine is clearly received in a way that Aquinas is not. Catholic and non-Catholic alike, the development of the church in the west is built with the influence of Augustine.
Of the later Fathers, we have such names as St. John of Damascus, who some consider the last of the Fathers. In the West, some consider the end of the Patristic era to be with Gregory; others would extend it to Saint Isidore who died in Spain in 636; others would extend it to the great English author and historian, Saint Bede, who died in 735. While there is obviously diversity in the authoritative “end” of the Patristic era, it is clearly sometime between the 7th and 8th centuries.
The Church Fathers are the guarantors of an authentic Catholic Tradition. Not only did they reflect upon and pastorally share the fruits of their contemplation with the early church, but they provide the link with those who walked with Christ Himself. They had a brilliant way of never separating theological insight from spiritual life, and they developed not only our way of understanding the fundamental truths of our faith, but developed the very language by which we do so. They are a guide to the belief and worship of the early Christians, and have led many non-Catholic Christians “back to Rome.”