Between 410 and 424, the Church of the East organised itself in a way that would have been familiar in the West. The Bishop of Seleucia-Ctesiphon was, if grudgingly, accepted as the Metropolitan, by the other five five sees into which the Church was ordered. But, as the Creed showed, the Church was autonomous, with its own liturgical language – Syriac – and its own liturgy. Any idea that all churches were in some way under the authority of Rome was an idea unknown in the East. It was the collision with the ecclesiastical and theological problems of the Church in the West which was to decisively shape the future, and fate, of the Church of the East.
My co-author has written on St Cyril of Alexandria and Nestorius and on the controversy over the nature of Christ, so I will not trespass on that here, except to say that the Church of the East was not involved in the controversy either at Ephesus in 431, or Chalcedon in 451, although it was profoundly effected by both.
Geographically, the Church of the East was closest to Antioch, and thus to its theological school. Although, as scholars now emphasise, one should not over-emphasise the term, the School of Antioch ‘ held a ‘Word/Man’ (Logos/Anthropos) Christology, which emphasised the complete humanity of Our Lord, including a soul; it tended to see the perfection and obedience of Our Lord as man as the root of our salvation; the Incarnation was ‘the word’ with a human body and soul. It grew out of a struggle against Appolinarian and Docetist notions of Christology, which tended to mean that at its extreme it could sound as though it was ‘adoptionist’ in the manner of Paul of Samosata; its classical representatives are often taken to be Diodore of Tarsus (c.330-390), Theodore of Mopsuestia (c. 350-430) and Nestorius of Constantinople. Because of its emphasis upon the two natures, it could be (and was by those in Alexandria on the look out for it) taken as preaching a doctrine of ‘two Sons’.
Because the Church of the East knew the West mainly through Antioch, and because its own Christology drew on the same roots – that is an historical approach with close-reading of the texts – it came under the same suspicion as they did at Ephesus and then at Chalcedon.
Nestorius, a pupil of Theodore, took the Antiochene view that it was the child of Mary who suffered and died on the Cross, and that therefore it was better to make this clear by calling her ‘Anthropotokos’ – mother of the man Jesus. That opened up several large chests of worms: the tendency of Antioch to write about two natures in a Dyophysite manner, and the fear of Alexandria, where the cult of the Theotokos was strong, that Constantinople was trying to push the Church in an heretical direction.
Here, if we are to understand what happened next, and why the Church of the East ended up being called ‘Nestorian’, it is necessary to say something about the theological terms used and about the languages in which they were expressed.