Christian bishop, theologian, later Saint. Augustine's starting point is a ringing affirmation of religious faith. ("Credo ut intelligam": "I believe in order to understand.")

He rejects the prodigal life of his youth (not so prodigal by modern standards but including an illegitimate son), a life vividly described and condemned in his Confessions, perhaps the most influential autobiography ever written. He also rejects the Manichaeism (see Manichaeus) of his youth, along with Donatism (see Donatus), Pelagianism (see Pelagius), skepticism, and Platonism (see Plato), although he incorporates elements of Neo-platonic mysticism into his theology. He accepts Aristotle's emphasis on happiness and on virtue as a means to happiness, but identifies virtue with love of God rather than with Aristotle's golden mean.

Augustine's entire thought, notwithstanding its reliance on logic and its sometimes dense metaphysics, including its defense of a doctrine of predestination, may be summarized by his saying: "Love [God] and do what you will."

Critics of St. Augustine charge him with nurturing an alliance between Church and State that leads to and justifies official persecution of non-believers.