The "Patristic Age", i.e. the age of "the Fathers of the Church", begins with the first theological commentaries of the Doctrine of Christ, a generation after the first Twelve Apostles, that is to say from the beginning of the 2nd century.
This age finishes at the time of the Great Schism, which separated the Byzantine Church (Orthodox) from the Latin Church (Catholic), in 1054 A.D.
St Justin is one of the very first known Fathers of the Church. He was born around 105 A.D. and he was the author of many writings of evangelization, including two famous Apologies for the Faith, which are the first treaties of Christian theology.
Among the fifty most well-known "Fathers of the Church" who distinguished themselves by their commentaries and other theological works between the 2nd and the 11th century, an interesting figure is that of St Iranaeus, from Smyrna, who became Bishop of Lyons in Gaul in the 2nd century. He had been a disciple of St Polycarp, who had himself been a student of St John the Evangelist.
The "Golden Age" of Patrology occurred between the 3rd and the 4th century. Many of the following names - in the the Eastern and the Western Church - and the important works on the theology of the Church present a profound illustration of the beginnings of the Christian era. There was, to mention only a few: St Athanase, St Ephrem (called the Cantor of the Virgin), St Basil the Great, St Gregory of Nazianzen and St Gregory of Nyssa, St Ambrose of Milan, St John Chrysostom, St Jerome, St Augustine of Hippo, St Cyril of Alexandria, etc.
From the 6th century, let us note in passing, among many others, the bishop-poet St Venatius Fortunatius, St Gregory the Great and St Maximus Confessor. In the 7th century, let us mention among several other saints, St Ildefonsus of Toledo, St John of Damascus (one of the masters of Marian theology in the East, along with St Andrew of Crete).
Later, in the 9th century, the Slavic people were favored with a great apostle in St Methodius. At the end of this great age, let us not forget St Fulbert of Chartres and St Michael Psellos.
After this comes... the Great Schism in the Church: the East left the hierarchical supervision of the Successor of St Peter, the Roman Pontiff, and thus gave birth to Orthodoxy as opposed to the Latin Church known as "Catholic".