Augustine is the most influential Christian writer who is not in the Bible, and the West argues with him rather than about him. The Confessions invented a genre. The City of God, written as Rome fell, gave Christianity its account of living under a state you do not control. His doctrine of original sin, his account of grace as unearned and irresistible, and his late anti-Pelagian writings are the raw material of the Reformation on both sides — Luther was an Augustinian friar, Calvin quoted him constantly, and Trent quoted him back. It is worth registering the parts modern readers find hard: he supplied the theory that justified state coercion of the Donatists, arguing from a parable that the church may compel people in; his views on sex and on the transmission of sin through it shaped Western attitudes for a thousand years; and he defended a hell of unending punishment against Christians of his own time who did not believe it. The Orthodox venerate him as a saint and regard large parts of his theology as the source of the West's problems.