St Gregory of Nyssa (c. 335 - c. 394) was a bishop and theologian – one of the great Cappadocian Fathers, renowned for defending Nicene Christianity and shaping the Church’s mystical theology. Preaching at a time when the liturgical calendar was still developing, Gregory helped promote the celebration of the Ascension as a distinct and joyful feast, emphasising Christ’s triumphal return to the Father and the raising of human nature into heavenly glory. This is one of his surviving sermons for the feast.