St Basil (c 330-379) was born into a saintly family in Caesarea, Cappadocia (Turkey); his brother was St Gregory of Nyssa, also a notable theologian. For some years St Basil lived in a monastic community before becoming Bishop of Caesarea in 370. He was a keen defender of the reality of the Incarnation against attacks from Arian heretics. St Basil also gave his name to a liturgy and a set of monastic rules which are still used in the East.
St Gregory Nazianzen (330-390), a friend of St Basil, was also from Cappadocia and involved in countering the Arian heresy. In 381 he became Bishop of Constantinople, although he had to retire to his native Nazianzus due to opposition. He was called “The Theologian” because of his great learning and talent for oratory.