I object to the separation of Constantinople from “Western civilisation “
Constantinople was an integral part of this Romano Greek civilization that we mistakenly call western.
The Roman empire fell in 1453.
Correct.
But the Western and Eastern halves of the Empire were split by the Islamics when they conquered Egypt in 641.
Just a few years later, the Islamics had conquered all of North Africa and most of Spain.
While the bulk of the Islamic fanatics were stopped at Constantinople, another important group was stopped in France, at the battle of Tours, by Charles Martel (732).
I highly recommend "Sword and Scimitar" by Raymond Ibrahim.