Saint Basil the Great (330 – 379) was bishop of Caesarea and a leading churchman in the 4th century. The Church considers him a saint and one of the “Cappadocian Fathers”, together with Saints Gregory the Theologian (Gregory Nazianzus) and John Chrysostom. The three are credited with development of the doctrine of the Trinity. The Roman Catholic Church considers basil a Doctor of the Church.
Basil lived during the years between the First Ecumenical Council (Nicea, 325) and the Second (Constantinople, 381), years in which it was uncertain whether the Church would stand by the declaration made at Nicea that the Logos (the “Word” — see John 1:1) was fully God, equally with the Father, or seek a more flexible formula in the hope of reconciliation with the Arians, who declared themselves unalterably opposed to the Nicene wording. Basil had been ordained priest in 362 in order to assist the new Bishop of Caesarea, whom he succeeded in 370. Since Caesarea was the capital, or metropolis, of the province of Cappadocia, its bishop was automatically the metropolitan of Cappadocia, which included about fifty dioceses (bishoprics). A metropolitan was roughly what we would call an archbishop, although in ancient terminology an “archbishop” was one step above a metropolitan. By that time, an Arian emperor, Valens, was ruling. Basil made it his policy to try to unite the so-called semi-Arians with the Nicene party against the outright Arians, making use of the formula “three persons (hypostases) in one substance (ousia),” thus explicitly acknowledging a distinction between the Father and the Son (a distinction that the Nicene party had been accused of blurring), and at the same time insisting on their essential unity.
Besides defending the Trinitarian faith against heresies, Basil was a model diocesan bishop. He visited every part of his diocese continually, he organized a great hospital for the sick poor, and like all ancient bishops he preached very frequently, some of his courses of sermons, which are major theological works, have been preserved. Heresy was by no means his only trouble. There was every sort of division among the Christians of the east and very considerable misunderstandings between east and west. Basil’s life as a bishop, in fact was lived in the midst of the sort of miserable muddles so common in the history of the church, when everybody is more or less in the wrong, no one trusts anybody else, and Christian charity is very little in evidence. His own charity never failed, and he worked unceasingly for peace and unity. But he was misunderstood and misrepresented; all his efforts to unite the faithful seemed to go wrong. He did just live to see the death of Valens, which meant the end of the Arian persecution: but he died very soon after, worn out, at the age of only forty-nine, on January 1, 379.