The Treatise De Spiritu Sancto and the Nine Homilies of the Hexaemeron

St. Basil the Great was Bishop of Caesarea, and one of the most distinguished Doctors of the Church. Born probably 329; died 1 January, 379. He ranks after Athanasius as a defender of the Oriental Church against the heresies of the fourth century. With his friend Gregory of Nazianzus and his brother Gregory of Nyssa, he makes up the trio known as "The Three Cappadocians", far outclassing the other two in practical genius and actual achievement.