The City of God is a great read. Some people enjoy reading history and its primary writers; for them the book is essential.
It is in a sense the first apologia for the fall of Rome to Alaric and the Goths in 410. Later, other authors such as Gibbon would place the blame for the fall of Rome on Christians. That was an error; for the fall of Rome was perhaps predestined by the end of the Republic and development of an imperial society with the upper classes becoming the globalists of their day while Rome itself was something of an afterthought where plebeians were pacified with bread and circuses while the rich were developing vineyards in France for hedonistic pursuits etc.
If one has read Augustine’s Confessions one learned something about the theologian-philosopher-author’s background. Augustine was well-educated and even understood the neo-Platonism of Plotinus. He was able to think about the nature of time and transcending issues concerning the city of God and the city of man comparatively. Augustine understood that transcendent Christian values surpassed the paradigm of the crumbling of imperial Roman rule.
Christianity became the unifying principle for what would become modern Europe a thousand years later. Christianity brought spiritual unification through the dark ages in the aftermath of the fall of the pagan European world with the faded glory of Rome perishing under foreign hooves.
The City of God is a kind of proto-evangelion for a lot of future philosophy and theology including protestant theologians such as Paul Tillich. Tillich in the 20th century noted the dichotomy of empirical political social outlooks that were somewhat cyclical or reciprocal. Specifically heteronomy, autonomy and theonomous social structures. Paul Tillich | American theologian and philosopher
Augustine and Tillich found dual time experiences in the now in regard to the point of view of existence one has. The City of God in some senses is reflected in the amillenialist position generally favored by the Catholic Church. The Kingdom of God is of the City of God, and the Kingdom of God exists in heaven and on Earth through the transcending presence of the Spirit of God in the hearts of believers. The viewpoint is consistent with post-tribulationist Protestant theology and differs from chiliasm or the belief in a pre-tribulation period with immanent apocalypse and Second coming of Christ