The Theodosian walls ......

The Theodosian walls were famously impressive and “they could hold off any conventional attack…But they had not been built to withstand bombardment by heavy artillery…” When the Ottoman bombardment began on April 6, 1453 - they had to face a new test in a new age of warfare

“Pride of place was taken by the huge cannon constructed by the Hungarian engineer Urban. It had been brought from Adrianople by 60 oxen and manned by 200 soldiers. When its deafening roar was first heard inside the city, people rushed into the streets in terror calling the name of the Lord. The cannonballs it shot weighed 12 hundredweight; and though it was an unwieldy and complicated piece of machinery that could only be fired seven times a day, it had a deadly effect in wearing down the ancient structure and the masonry of the walls. The smaller guns added their contribution to the damage, and before many days were out a section of the outer wall had collapsed into the moat.”

At night the defenders would go out and try to repair the damage as best they could, despite the “sickening monotony” of daily bombardment by the Ottomans. However, despite all this, it is not like the walls were ever totally destroyed. It took great concentrated effort over many weeks to heavily damage select sections of the walls. 

The defense of Constantinople never failed simply due to cannons destroying the walls. It was multi-faceted. The defenders were too low in number. Mehmed was able to get ships inside the Golden Horn and attack the sea walls, forcing some of the limited numbers of soldiers to be diverted there. The walls did take damage over time, and the moat in front of the walls was gradually filled with rubble and degree making Turkish assaults easier. Despite all these problems, the defenders were doing surprisingly well in repelling the final assault of the Ottomans until the commander of the defense, Giovanni Giustiniani Longo, was mortally wounded. It had been him and his elite heavily armored Genoese troops which had been holding back the enemy. Even in the breaches the cannons had made, they had valiantly held back the numerous Ottomans

Once Goustiniani retreated and his crucial troops left the fight, the Turks continued their ferocious assault and the defense collapsed soon after. Thus, Mehmed’s final gamble paid off. Constantine XI and his soldiers died in the struggle and the city of Constantinople fell for a second and final time. However, it was NOT a simple story of cannons destroying the ancient walls. All things considered, the Theodosian walls did very well to hold up against cannons for such a long period of bombardment , a scenario it’s architects could never have imagined!

Source: The Last Centuries of Byzantium, 1261-1453 by Donald M. Nicol

Artist: unknown, I saved this photo a long time ago in my phone and don’t know who made it. If you do, please mention it