This post shall be me playing Devil's Advocate with Post-Millenialists and Partial Preterists, by arguing that their eschatological position does not necessarily require allegorizing the time period of The Millennium.
There is a common misnomer out there that believing in a Literal Thousand Years means believing The Kingdom of that time period ends at some point, which is why you occasionally see an argument that the Nicene-Constantinople Creed's quotation of Gabriel in Luke 1:33 somehow was specifically a refutation of Pre-Mil. However the only thing Revelation 20 explicitly says happens exactly a Thousand years later is Satan being let out of the Abyss, he then stirs up Gog and Magog and they besiege the "Beloved City" however their siege fails. Revelation 21 and 22 are about the separation between the spiritual and physical finally completely ending, not about a completely New Messianic Kingdom starting. The Greek word translated New in those chapters isn't Neo which I wrote an entire post on already.
Now at face value it seems like everything from Satan being let loose to the White Throne Judgment happens pretty rapidly. But that's because we're reading a summary, maybe it will happen quickly but it could theoretically all take decades, centuries or maybe even another thousand years to play out.
So Post-Mils and Partial Preterists do have the option to consider identifying The Millennium with an exactly one Thousand year time period of recorded Church Age history, and placing us right now in Revelation 20:9 with the "Camp of the saints" being understood spiritually rather then tied to a specific geographical location.
And in that context I have a few hypothetical models to propose, because even though I'm not Post-Mil currently I have considered it.
But first I want to address how most of these models implicitly identity the "Hoards of Gog and Magog" with principally the Turks and perhaps by extension other Altaic peoples like the Mongols. This part of Revelation is among the Bible passages that have been abused by White Supremacists so I want to make myself clear, IF any of these interpretations are true it's about the Turks having a specific role to play in God's plan, however I believe in Universal Salvation meaning all of them are still Children of Adam who God Loves as much as everyone else. So do not use this material to justify being Racist.
Now on to the hypothetical Millenniums.
I place the end of the 70 Weeks of Daniel in 37 AD one Week following the Crucifixion, Resurrection and Pentecost in 30 AD, which I argued for on this blog years ago. Low and behold 1037 AD is the beginning of the reign of Tughril the first Sultan of the Seljuk Turks. It was under his leadership that the Turks first moved south of the Gates of Alexander into Persia.
However it was under Alp Arslan and Malik Shah that the Seljuk Turks first came into conflict with "Christendom" around 1070 AD. The significance of 1070 minus 1000 I shouldn't need to explain to Preterists.
In 1135 AD a thousand years after the defeat of the Bar-Kochba Revolt Seljuk Ruler Imad Al-Din Zengi crossed the Eurphrates River. 1137-1144 contained other notable events.
Later in the early 1300s a Thousand years after Constantine is when the Ottomans under Osman I and Orhan and other Turkic Tribes conquered deeper into Western Anatolia capturing what had long been core Byzantine territories including the cities that housed the 7 Churches of Revelation 2-3. They besieged Nicaea just a few years after the one thousand year anniversary of the Council of Nicaea. 324 was the year Constantine defeated Licinius and began the founding of Constantinople, 1317-1326 was the Seige of Bursa which secured Ottoman control of most of Asia Minor with only the core area around Constantinople still free.
The decade from 380-390 is when Theodosius I firmly established Christianity as the State Religion of the Roman Empire. Ticonius published the first real Post-Millennial interpretation of Revelation in 380. A thousand years later 1380-1390 would be when the Ottoman Empire really began entering Europe.
The Fall of Constantinople to the Ottomans was in 1454 BC, about 3 years following the Millennial Anniversary of the Council of Chalcedon.
There isn't a single event in the reign of Emperor Justinian that doesn't have it's Millennial anniversary during the reign of Suliman The Magnificent. I actually already made a post on arguing for Bible Prophecy being fulfilled in the time of Justinian, that was mainly in the context of playing Devil's Advocate with Historicism, but it can be adapted for this purpose.
Some people have an odd fixation on viewing Bible Prophecy from an Anglo-Centric POV. Interestingly the Christianization of the Anglo-Saxons was pretty complete by 640. One thousand years later and 1640 is when the English Civil War starts.