The grand strategy of Christianity in relation to the world is something that I find myself speculating upon from time to time.
Given the long wait of the ancient Hebrews for Messiah, it would seem that there needed to be social preconditions for the Incarnation to stand its best chance of achieving its goals.
Because human free will is real, and Men are and were free to reject salvation; so social conditions - specifically the state of Mens' minds - is important; thus God must work with society, as best as may be.
It would seem that the pagan Roman Empire provided the best chance for the Gospel - since it was both multi-national and highly religious (multi-religion): providing the optimal possibilities for the new faith to spread (i.e. the best chance that many Men would choose Christ).
It is to the credit of the many individuals who embraced Christianity under the pagan Emperors, that the Empire swiftly became Christian with the foundation of the Second Rome at Constantinople.
The Christian Roman Empire endured for over a thousand years; after which a Third Rome (self-consciously so) emerged in Moscow - to end utterly in 1917.
Always it seems that God works to spread his Gospel; and Empire is one way this may happen - but only if Men will it.
Many Empires have arisen in Christendom, and it is as-if some were hoped, or perhaps intended, to become the site of the Fourth Rome and a new Christian Roman Empire.
Medieval and modern Western Europe as a whole had opportunities, but in the end Men chose schism and warfare over the possibility of Christian Empire; and the individual states rejected Christianity as the focus of their societies, hence incipient Empires were not primarily Christian and missionary, but at best the Gospel would follow-behind commercial and military priorities.
Perhaps Madrid, or Paris, or Amsterdam, or London, or Berlin was meant to be a Fourth Rome - but no, it did not happen.
Meanwhile, a New World was found; and North America became a focus of Christian hopes, then a place where the ground was prepared by phases of revival.
Perhaps there was the divine intention of a North American Christian empire with Philadelphia as the Fourth Rome?
But the US people en masse, as a whole, chose otherwise; and descended into civil war, materialism, another civil war, and modernity.
The emergence of Mormonism was another chance, with great possibilities and remarkable achievements emerging rapidly and very obvious - but the national response was instead to seek extermination of the budding movement; again, and again, and again.
Extermination of the Mormon religion was the national, indeed, international, choice of Men.
The policy of extermination failed in that objective; but the policy nonetheless successfully prevented what might, perhaps, have become a Mormon Empire; with Salt Lake City emerging as the Fourth Rome.
Behind all this I imagine Jesus Christ working tirelessly to expand the possibilities of spreading His Gospel - often aiming at the 'ideal' of a Christian Empire - a Fourth Rome, a Third Byzantium; but always, necessarily, working via the free choices of Men.
Also, I imagine the workings of His Adversary Satan and his minions; also tireless in his spreading of lies, encouragement of hatred, selfishness, short-termism; destruction of beauty and virtue...
...focusing his destructive efforts often on any budding hopes of Christian Empire...
...aiming to subvert, destroy and invert; aiming to infiltrate and convert any existing Good Empire into a Demonic Empire.
(...such as The West has now become - reaching-out internationally to attack Good, to destabilize and foment civil violence and war. The demonic Empire of the West may seem to be a failure - and by conventional military standards it surely is - but in the past fifteen years it has triumphantly succeeded in facilitating, enabling and concealing the torment and killing of millions of Christians worldwide; especially in the Middle East and Africa. Clearly, at some level, that is its primary strategy.)
It really is much, much easier (requires less time, effort, resources) to destroy than to create order.
It is easier to pursue short-term and selfish goals than to love patiently.
Hence Good is always swimming against the stream of natural resistance.
In the end, the prophecies are of utter failure, on this earth - with destruction of the world.
This world is doomed as surely as Ragnarok seemed inevitable to the Norse pagans; and the Giants of disorder and destruction shall eventually triumph despite the courage of the heroes.
Yet Ragnarok will be (and is being)
delayed; for so long as fresh souls are being
Ragnarok will happen, the pagans were correct about that; but Christians know there is another and better world to come after Ragnarok - and that makes all the difference.