Minas Tirith as Constantinople?

[The Sixth Wizard]

I have recently been reading quite a bit about Medieval history, and one thing that struck me was the similarity between Gondor and the late Byzantine Empire.

• Gondorians are from a fallen city across the sea, which fell from prominence. This would be Rome... The religious differences between the 'faithful' and the King's Men could be interpreted as the Great Schism.
• Gondor and Byzantium are in gradual decline, but the thing I noticed was that both were losing old technological secrets. Their old technologies were the things that were letting them hold on for so long (Greek Fire, Numenorean walls, etc.)
• The western heavy knights that reinforced Byzantium throughout the ages could be the Rohirrim.
• Both had held far-off lands before, but had been pushed back to nearly a single city.
• The Ottoman navy was a key factor in the fall of Constantinople (Corsairs).
• Both were the only powers at the time to employ scouting (rangers).
• Both wars saw the use of gunpowder for practically the first time, only on the 'evil' side (see Great Turkish Bombard on Wikipedia)
• **very interesting** The symbol of the city of Constantinople was a moon. (though technically the symbol of Minas Tirith was a sun, but whatever...)

And numerous more I'm sure. These are probably just coincidences, but they were interesting to compare. Do you think Tolkien derived some of the story from the Byzantine Empire's fall? In which other places in the book are similarities with real history?

(by the way, yes, this is what I was obsessed with after going off the Downs for a few months )