At Milan, Augustine abandoned the Manichaean faith and fell under the spell of Ambrose, the bishop of Milan. Better educated than Augustine, a superb preacher, indifferent to the demands of the flesh, Ambrose stimulated Augustine to reexamine all his ideas. And Augustine’s mother, who had followed him to Milan, eagerly drank in Ambrose’s words “as a fountain of water.”
Augustine liked the Neoplatonist idea that material things of this world were reflections of ideas in the eternal other world, and that there were means by which one could move away from the external world of the senses. Augustine’s world widened. Evil, instead of looming at the center of it, took a less prominent place; his god became more distant, more powerful, more mysterious than Mani’s god. But in the end Augustine could not accept the Neoplatonist view that a person could attain to the vision of god by reason alone. He was ready for conversion to Christianity.
This was a major step, involving not only the abandonment of his worldly career but also the rite of baptism, which was then felt to be so great a spiritual ordeal that many Christians put it off until their deathbeds. At Easter 387, aged thirty-three, he was baptized by Ambrose. Soon afterward he returned to his native North Africa.
In his hometown he soon found himself in intellectual combat with the Manichees, debating them publicly, writing pamphlets against them, arguing that evil was in large part simply bad habits; once a person had derived pleasure from an evil act, the memory of the pleasure prompted doing it again. Within three years Augustine had been forced into the priesthood by the demands of a local congregation, and in 395 he became bishop of the large town of Hippo (modern Bone). Here he wrote The Confessions, describing his spiritual journey in an effort to lead his reader to God.
Augustine’s gravest practical problem was the Donatists, who regarded themselves as the only true church and who outnumbered the Catholics in Hippo. He preached against them, wrote pamphlets against them, turned out a popular set of verses satirizing them. Convinced that there could be no salvation outside the church, Augustine also persecuted the Donatists after 399, when the Christian emperors began to take severe measures to suppress paganism.
When the Goths sacked Rome in 410, refugees poured into North Africa with accounts of the fear that had gripped the inhabitants and the ruthlessness of the barbarians. Though no longer the imperial capital, Rome was still the symbol of the imperial tradition and of all ancient culture. The North African governors, worried about the stability of the province, issued an edict of toleration for the Donatists. Augustine protested, contrasting the City of Man, the secular world where evil was commonplace, with the City of God, toward which history was moving humanity spiritually.