Basil of Caesarea
Bishop of Caesarea in Cappadocia, theologian and one of the three 'Cappadocian Fathers' (330–379), together with his younger brother Gregory of Nyssa and his friend Gregory of Nazianzus, educated in rhetoric and philosophy at Athens — where he studied alongside Gregory of Nazianzus and, according to tradition, also the future emperor Julian the Apostate — and who, after a period of solitary ascetic life, became one of the decisive architects of orthodox Trinitarian theology and of Eastern Christian monasticism. His most influential theological work, On the Holy Spirit (De Spiritu Sancto), completed the formulation of Nicene Trinitarian doctrine by arguing, against the Pneumatomachians who denied the divinity of the third person, that the Holy Spirit must receive worship and glory together with the Father and the Son, a decisive contribution that paved the way for the definitive formulation of the Trinity at the Council of Constantinople (381). As an organiser of monasticism, his Longer and Shorter Ascetic Rules — sets of questions and answers on communal monastic life — established a model of moderate cenobitism centred on work, communal prayer and active charity toward the poor, exerting lasting influence on both Eastern monasticism and, through Saint Benedict, Western monasticism. Bishop of Caesarea from 370, Basil was also notable for social action extraordinarily ambitious for its time: near Caesarea he founded a monumental charitable complex known as the Basiliad, combining a hospital, a hostel for pilgrims, a hospice for lepers and a soup kitchen for the poor, regarded as one of the earliest great hospital complexes in Christian history. Venerated as a Doctor of the Church under the byname 'the Great', his Liturgy of Saint Basil continues to be celebrated today in Eastern Orthodox churches on especially solemn liturgical occasions.