Varro's Theology
Augustine uses the scholar Varro’s categorization of theology (mythical, civil, natural) to systematically dismantle the intellectual foundations of Roman religion.
The Nature of Angels
The fall of the angels precedes the fall of man, establishing that the conflict between good and evil is cosmic, not merely human.
Virtue and Glory
Augustine distinguishes between Roman virtue, which seeks glory, and true virtue, which seeks piety. The former belongs to the Earthly City, the latter to the City of God.