Augustine addresses City of God to Marcellinus, a friend and statesman who had requested Augustine’s aid in answering the proconsul Volusianus’s questions. Volusianus was concerned that Christianity had weakened the Roman Empire, especially in contrast to Rome’s former strength when it had served pagan gods. This objection had become the subject of broad debate in the aftermath of the sack of Rome in 410 CE by Alaric and the Visigoths. Augustine sums up his aim in the Preface of Book 1: “I have taken upon myself the task of defending the glorious City of God against those who prefer their own gods to the Founder of that City” (5). Augustine asks his readers to consider the fact that in Alaric’s sack of Rome, the Visigoths showed mercy to all those who took refuge in Christian churches and shrines, a striking act of clemency. He contrasts this with the failure of pagan gods to protect their worshipers in other well-known historical battles, such as the fall of Troy.

Augustine argues that history teaches that both good people and wicked people are afflicted by tragedies, and so it should come as no surprise that one’s own capital city might fall to calamity, regardless of its religious affiliations.