May 29, 1543 marks the wall of Constantinople to the Turks and the final destruction of of Eastern Roman Empire. It also started the Muslims crusades to conquer Europe from the east, since they had been turned back at Tours in 732 by Charles Martel and his Frankish warriors. Emperor Constantine XI died fighting. His remains were never recovered. A day that impacts our world still.
https://en.wikipedia.org/wiki/Fall_of_Constantinople