The story of Western Christianities from Constantine to the close of the sixth century is one of both expansion and the formation of diverse Christianities. The themes that were in evidence across the Christian West throughout the period under consideration: political transformation and the formation of competing orthodoxies, the Christianisation of Western aristocracies, and the interplay between political and ecclesiastical structures. This chapter discusses the endorsement of bishops of the Nicene orthodoxy, the adherences of Roman Christianities by the provinces of Italy, Gaul, Spain and North Africa, to Nicene orthodoxy. As schisms within the churches of the Nicene tradition broke out after Chalcedon, the emperors and bishops of Constantinople faced the consequences. In the autumn of 482, Emperor Zeno addressed a letter to the Alexandrian church that proposed a compromise formula drafted by Acacius of Constantinople. Pope Vigilius had an aristocratic background and exemplified the trend towards the aristocratisation of the papacy.

The grouping together of Basil of Caesarea, with his friend, Gregory of Nazianzus, and his brother, Gregory of Nyssa, as the 'Cappadocian Fathers' is a product of modern scholars, who have regarded as significant the family links, geographical locality and common theological commitment they perceived in them. Theodosius was committed to Nicene orthodoxy and soon invited Gregory of Nazianzus to Constantinople, a largely Arian city, to be orthodox pastor in the Church of the Resurrection. He preached eloquently in defence of Nicene orthodoxy, his sermons there including the five theological orations to which he owes his title 'the Theologian'. The writings of Basil the Great can be divided into several categories: ascetic works, dogmatic works, homiletic works, letters, and a liturgy. Gregory of Nyssa seems to have been the Cappadocian for the twentieth century. There are a large number of dogmatic works, the most important of which is his Against Eunomius.