If, as posited in the last post on this theme, the fifth and sixth centuries are the era of the development of the concept of ‘Fathers’ of the Church, it is worth noting that this also the era of the unsolved Christological crises, beginning with the accession of Nestorius to the See of Constantinople in 428.
Normally, we imagine that the ‘Nestorian problem’ was dealt with in 451 at the Council of Chalcedon, but the history of Byzantine Christianity demonstrates how far wrong we are in such an assessment. Not only was there an uprising in Palestine against Juvenal, Bishop of Jerusalem, there was also a general uprising throughout Egypt in favour of Dioscorus, the ‘Miaphysite’ (Monophysite — highly conservative Cyrillian) Patriarch who opposed Chalcedon’s Latin, Leonine settlement.
Theologians throughout the eastern Mediterranean were opposed to Chalcedon, and their opposition did not die down with time. As one generation of Mia/Monophysites died, a new generation rose up to take its place. Thus we move from the generation of Dioscorus to that of the brilliant representatives of that movement, Philoxenus of Mabbûg and Severus of Antioch. They would in turn be succeeded by the likes of John of Ephesus and Jacob Baradaeus (two of the founders of the Syrian or ‘Jacobite’ Orthodox Church). Dioscorus’ most recent successor, who was part of a line from him through the likes of Timothy Aelurus (‘the Weasel’), Pope Shenouda III, recently died.
On the other hand, despite the accusations of ‘Nestorianism’ hurled at Leo and Chalcedon by Severus of Antioch and his fellow Miaphysites, those Christians who saw themselves as in line with Nestorius found themselves forcibly excluded from the Roman Empire under Justinian in the early sixth century; they accordingly went to Persia and beyond, forming the ‘Church of the East’, and have had the misnomer ‘Assyrian Orthodox’ applied to them in the past. In Diarmaid McCulloch’s A History of Christianity, you can see a photo of a Chinese monastery founded by the Church of the East in the Middle Ages as well as a stele with both Chinese and Syriac on it, showing a Christian thoughtworld sensitive to local Taoism. Modern scholarship seems to have taken to calling the Church of the East and its historical forebears ‘Dyophysite’, a term that I feel muddies the waters, because it could be applied to Latin and Chalcedonian theology just as easily.
The years following 451, in other words, were not a time of Christological ease and theological straightforwardness. Everyone was vying for position as the accepted orthodoxy of the imperial church, especially the Chalcedonians and the conservative Cyrillian Monophysites.
As they fought and argued and sought to prove that they were the true successors of the Apostles and the Holy Fathers of Nicaea, both sides were busily pushing forth the same theologians as evidence for their orthodoxy. In a world already relatively traditionalist, the traditionalism of the succeeding generations of Christologians was sealed. To prove they were truly orthodox and in line with tradition, out would come Sts. Athanasius and Gregory of Nyssa and Gregory of Nazianzus and Cyril of Alexandria. Both sides would distance themselves from Nestorius and Eutyches.
A major result of this traditional, patristic approach to doing theology is that both sides pretty much have the same Church Fathers for the period before 451. The possible exceptions are Theodoret of Cyrrhus and Ibas of Edessa, who had particular teachings condemned at the Second Council of Constantinople in 553 during the Three Chapters Controversy, much to the chagrin of many western bishops — the eastern bishops, who felt these men and their positions too ‘Nestorian’, were willing to grant this concession to their Miaphysite opponents.
After 451, the traditions mostly diverge, although Abba Isaiah of Scetis, from an anti-Chalcedonian monastery in Gaza, is among those ascetics revered by both sides of the conflict surrounding Chalcedon. Thus, Leo the Great and Maximus the Confessor are Church Fathers to the Chalcedonians, while Severus of Antioch and Philoxenus of Mabbûg are Fathers to the anti-Chalcedonians, and Theodore of Mopsuestia and Nestorius are Church Fathers of the ‘Nestorians’.
What this also shows us is that a Church Father is not simply any ancient Christian writer. Not for the people who were alive in the fifth and sixth centuries — let alone the rest of the Byzantine and Mediaeval worlds — at any rate. It may be healthy for us to have Severus of Antioch in the Routledge Early Church Fathers Series alongside Leo the Great. It is probably not so bad to read the exegesis of Julian Eclanum beside Augustine of Hippo, or Theodore of Mopsuestia with Cyril of Alexandria. But for many Christians of much of the history of Christianity, these pairs of authors are not pairs of Fathers, but of a Father and an opponent, a heretic even.