Even the stormy days of the last persecution yielded some considerable writers, such as Methodius in the East and Lactantius in the West.
In the 4th century Pamphilus, Eusebius of Caesarea, Athanasius, the Cappadocians, Didymus, and Rufinus were on the side of Origen against the attacks of Methodius and many others.
The chief result of the alliance with the latter was the conversion of the Moravians to Christianity by two Greek monks, Cyril and Methodius, despatched from Constantinople (863).
The attempts of Methodius of Tyre at the beginning of the 4th century and Apollinarius of Laodicea about 360 to defend chiliasm and assail the theology of Origen had no result.
All writers earlier than the 5th century are valuable, but particularly important are the following groups: (1) Greek writers in the West, especially Justin Martyr, Tatian, Marcion, Irenaeus and Hippolytus; (2) Latin writers in Italy, especially Novatian, the author of the de Rebaptismate and Ambrosiaster; (3) Latin writers in Africa, especially Tertullian and Cyprian; (4) Greek writers in Alexandria, especially Clement of Alexandria, Origen, Athanasius and Cyril; (5) Greek writers in the East, especially Methodius of Lycia and Eusebius of Caesarea; (6) Syriac writers, especially Aphraates and Ephraem; it is doubtful whether the Diatessaron of Tatian ought to be reckoned in this group or in (1).