@elston_ You can call them "pagans", like a Jew would, but they were just Roman citizens, who saw that Christianity was also to blame for the fall of the Empire, thanks in large part to Emperor Constantine.

Augustine wrote the books to defend Christianity and in them he explains that Christians should disassociate Rome (the earthly kingdom) from their true home (the city of God/heaven). He denounced Rome's history forged on pride and conquest, and instead preaches "humility and love", etc.