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 before embarking on a spiritual journey. After moving to Rome and Milan, he was baptized by Bishop Ambrose and went on to become the Bishop of Hippo. As a spiritual leader, Augustine wrote two influential books, The City of God and Confessions, which profoundly shaped Christian doctrines around original sin, predestination, and the subordination of temporal rulers to bishops. His philosophical works had a significant impact on the development of Christianity in Europe.