Saint Augustine

Born in Roman North Africa to a pagan father and a Christian mother (Monica) who prayed for his conversion for decades. He spent his youth chasing women, rhetoric, and the Manichean heresy — "Lord, make me chaste, but not yet." A long, restless intellectual journey brought him through Neoplatonism to Christianity at age 31, recounted in the Confessions — the first true autobiography in Western literature, written as a sustained prayer. As Bishop of Hippo he wrote City of God in the wake of Rome's sack, distinguishing the city of man from the city of God. His doctrines of original sin, grace, and the restless heart have shaped Western Christianity — Catholic and Protestant alike — for sixteen centuries.