When considering what Augustine set out to do when he wrote the City of God one must realize he was not actually trying to write a historical account of the sacking of Rome or even its implications.

When the days are evil, when hurt and confusion prevail, when uncertainty pervades every thought, and when our faith is weak; may we draw near to each other in the congregation of the Saints to draw encouragement, so that we do not waver from the profession of our most Holy Faith.