Why was Constantinople so hard to conquer?

The city of Constantinople was difficult to conquer because of their diligent use of ramparts and impressive city walls that protected them from invaders from outside. The fortifications used by Constantinople for the protection was some of the best of that time, and theirs was seen as a prevalent model that others followed throughout the Mediterranean region and Europe too.

The capture of this city and others associated with it truly indicated an end to the Byzantine Empire, which was a continuation of the Roman Empire dated back to 27BC, ultimately lasting for an impressive 1,500 years. This conquest of Constantinople was a massive blow to Christendom by the Muslim Ottoman military. After this conquest, they seemed to be left on their own to advance into Europe, seemingly without any adversaries.

Conquering Constantinople was difficult for invaders as this city has complex and high walls surrounding it. Constantine I, built the first wall that secured both sea and land fronts following the erection of the famous walls, the Theodosian Walls, that were about 2 kilometers and were double walls.

These walls were so thick that they can serve as a storage of tons of grains and if they would want, of their riches. The high walls were guarded by archers that can fire upon enemies miles away. An enemy archer would find it difficult to shoot from the ground as the Constantinople’s archers were in a more strategic location for both offense and defense.