The sack of Rome by the Visigoths in 410 left Romans in a deep state of shock, and many Romans saw it as punishment for abandoning traditional Roman religion for Christianity. In response to these accusations, and in order to console Christians, Augustine wrote The City of God, arguing for the truth of Christianity over competing religions and philosophies and that Christianity is not only not responsible for the Sack of Rome, but also was responsible for the success of Rome. He attempted to console Christians, writing that, even if the earthly rule of the Empire was imperiled, it was the City of God that would ultimately triumph. Augustine's eyes were fixed on Heaven, a theme of many Christian works of Late Antiquity, and despite Christianity's designation as the official religion of the Empire, Augustine declared its message to be spiritual rather than political. Christianity, he argued, should be concerned with the mystical, heavenly city, the New Jerusalem-rather than with earthly politics.
The book presents human history as being a conflict between what Augustine calls the Earthly City (often colloquially referred to as the City of Man) and the City of God, a conflict that is destined to end in victory for the latter. The City of God is marked by people who forgot earthly pleasure to dedicate themselves to the eternal truths of God, now revealed fully in the Christian faith. The Earthly City, on the other hand, consists of people who have immersed themselves in the cares and pleasures of the present, passing world.
Augustine's thesis depicts the history of the world as universal warfare between God and the Devil. This metaphysical war is not limited by time but only by geography as it takes place on planet Earth. In this war, God moves (by divine intervention/ Providence) those governments, political /ideological movements and military forces aligned (or aligned the most) with the Catholic Church (the City of God) in order to oppose by all means-including military-those governments, political/ideological movements and military forces aligned (or aligned the most) with the Devil (the City of Devil).
Jacques-Bénigne Bossuet's Discours sur l'histoire universelle or Speech of Universal History (1681) is considered by many Catholics as an actual second edition or continuation of The City of God. In this work Bossuet continues to provide an update of universal history according to Augustine's thesis of universal war between those humans that follow God and those who follow the Devil.
This concept of world history guided by Divine Providence in a universal war between God and Devil is part of the official doctrine of the Catholic Church as most recently stated in the Second Vatican Council's Gaudium et Spes document: "The Church . . . holds that in her most benign Lord and Master can be found the key, the focal point and the goal of man, as well as of all human history...all of human life, whether individual or collective, shows itself to be a dramatic struggle between good and evil, between light and darkness...The Lord is the goal of human history the focal point of the longings of history and of civilization, the center of the human race, the joy of every heart and the answer to all its yearnings." (From Wikipedia)