St. John Cassian
O God, come to my assistance; O Lord, make haste to help me.
— Conferences X – the prayer Cassian recommended
He travelled to the monks of the Egyptian desert to learn prayer from them and carried their wisdom to Gaul. He founded monasteries in Marseille. The short prayer “O God, come to my assistance,” which he recommended, is still prayed at the start of every hour of the Divine Office.