Augustine of Hippo

Augustine of Hippo (354–430) was the most influential theologian of the Western church, born in Roman North Africa to a pagan father and Christian mother (Monica). Educated in rhetoric at Carthage, he passed through Manichaeism before his celebrated conversion in Milan under Bishop Ambrose, recounted in his Confessions. Returning to Africa, he founded a monastic community and was ordained, then consecrated bishop of Hippo Regius, where he wrote the City of God and hundreds of letters and sermons. He died on 28 August 430 during the Vandal siege of Hippo, having shaped Catholic doctrine on grace, original sin, and the Trinity for all subsequent centuries.