This was written by St. Augustine to show that salvation is attained by the worship of the one true God and by the rejection of all false gods.
As a challenge to the Roman neo-paganism that threatened to overwhelm Christianity in the early fifth century, it embraces religious lore, philosophy, theology and history.
Augustine discusses first the ancient polytheistic religion of Rome; secondly, the arguments of the Greek philosophers, with emphasis on the Neo-Platonists; last, creation, time and eternity as presented in the Bible. His thesis is that Rome, as the earthly city of God, should bring together the revelation of the Bible, the wisdom of Greek philosophy and the honor and dignity of her own tradition, and so enable the members of her church to enter into the eternal City of Heaven through regeneration in Christ. In representing this thesis, Augustine created a charter for a Christian future that has become one of the great cornerstones in the history of Western thought.