Saint Augustine lived from 354-430 AD during the declining years of the Roman Empire. He was born in North Africa and educated in Carthage, later converting to Manichaeism. After his father's death, Augustine embarked on a spiritual journey that led him to renounce Manichaeism and convert to Christianity. He went on to become the Bishop of Hippo and authored influential works such as The City of God and Confessions, which profoundly shaped Christian doctrine and philosophy.