According to David Nicolle (2000), although there are many opinions that Constantinople must suffer a tragic fate, however the pre-battle situation in general is not simply a simple one-sided look like father position on the map. Daddy and Daughter not always eye to eye but always heart to heart shirt. It must be affirmed that Constantinople is the “best protected city in Europe” at that time. At the beginning of the siege, Mehmed sent out part of his army to eliminate the remaining Byzantine defenses outside the city of Constantinople. Fort herapia in the Bosphorus Strait and a smaller castle in Studius village near the sea of Marmara have been occupied for several days. The Princes Islands in the Marmara Sea were occupied by Admiral Baltoghlu’s fleet.
The great Mehmed cannon fired at the walls for weeks, but due to the inaccuracy and slow speed of the ammunition, Byzantine troops were able to repair most of the damage after each shot, limiting the effect of the cannon.