The Engineering behind the Ottoman Conquest of Constantinople
Ibrahim Safi – American Muslim Society for Science, Engineering, and Medicine
May 29, 2026, marked the 573rd anniversary of the Ottoman victory over Constantinople, an event predicted by Prophet Muhammad (peace and blessings be upon him) in the famous narration:
“Verily you shall conquer Constantinople. What a wonderful leader will her leader be, and what a wonderful army will that army be!”
Narrated by Abdullah ibn Bishr al-Khathʿami and recorded in Musnad Ahmad ibn Hanbal.
The man to fulfill that prophecy was Sultan Mehmed Fatih (Muhammad al-Fatih), otherwise known as Mehmed the Conqueror. The task standing before him, conquering the seat of the Eastern Roman (Byzantine) Empire, was daunting, one many had tried, and many had failed. Constantinople was guarded by the mighty Theodosian walls, constructed on the orders of Anthemius, regent to Emperor Theodosius the Second, during the early 5th century. For a millennium, the walls had seen many who sought to conquer them: The Huns, the Goths, the Avars, the Slavs, the Persians, the Umayyad Caliphate, the Bulgars, the Rus, the Crusaders, the Venetians, and previous Ottoman attempts (Agoston and Masters).
The Umayyad sieges were critical and are believed to have been two separate sieges. The first siege was commanded by the caliph Mu’awiya (may Allah be pleased with him), and one of the key notables of the siege was Abu Ayyub Al-Ansari, a companion of the Prophet (peace and blessings be upon him). The second siege, often believed to be the closest to victory for the Muslims until the final siege, was led by Maslama ibn Abd al-Malik, who was the brother of the incumbent caliph Sulayman ibn Abd al-Malik. However, these sieges, and all the failed attempts by others, faced one key obstacle: The Theodosian walls, large and wide, with several layers and guard towers. The mightiest of armies fell before these walls. This was the challenge befalling Sultan Mehmed Fatih, one that required an engineering solution.
Earlier, the invention of Gunpowder, first by the Chinese for fireworks, later for basic incendiary weapons, and eventually by both European and Middle Eastern powers, enabled the development of early cannons. The key breakthrough in this technology was the shift from incendiary weapons, which attempted to project fire, to using the force of the gunpowder explosion to propel projectiles. In this sense, the Ottoman revolution in cannon-making was truly groundbreaking. Previously, cannons had been used on battlefields and in limited sieges, usually to breach castle walls, but this was still insufficient to breach the Theodosian walls (Crowley).
Sultan Mehmed hence commissioned the cannoneer Orban, a well-renowned engineer of his time, to build for him the greatest cannon the world had ever seen, one that could break the Theodosian walls, a cannon larger than all others. This, of course, presented a significant engineering problem: all cannons at that time were cast, and, typically, the larger the body, the greater the risk of deformation and brittle shattering. Not only that, but firing a bombard weighing 15-25 tons, sufficient to break the walls, would put a significant strain on the cannon body itself (Crowley).
To remedy this, a bronze alloy with the correct ratio of copper and tin had to be cast to ensure proper ductility and tensile strength, thereby ensuring the weapon's performance. However, unlike modern foundries where such materials are readily available, the copper and tin had to be mined, smelted, refined, and transported, a task that required imperial logistics, something Sultan Mehmed was able to provide. The next challenge was setting the cast itself, which required melting the metals and fitting them into the mold. However, one does not simply melt 20 tons of copper and tin, which requires a sustained, intense heat source. Too little heat and segregation of the alloy can occur; too much heat and shrinkage defects can occur; and, unlike modern casting facilities, the temperature could not be controlled in such a disciplined manner (Biringucci).
Another obstacle was that the cannon's mold would have to be very large. How could it be made? Orban implemented some of the latest technologies of his time, relying on timber frameworks and clay to create a precise mold that would allow the cannon to be set. In addition, the cooling of the body itself is an often-overlooked challenge, even in modern casting processes. If not handled properly, residual stresses can remain, and warping may occur, resulting in earlier fractures and reduced structural integrity of the final body. Orban remedied this by insulating the mold with dirt and allowing it to cool over an extended period, from several days to a week, depending on the cast temperature and materials used. In modern manufacturing, cooling is regulated with heat exchanger systems paired with insulation, which itself is planned with computational software, a rigorous task today, much less almost 600 years ago (Biringucci).
Another overlooked part of this engineering project is the transportation of this cannon from the factory near Edirne, the former capital of the Ottoman Empire, to Constantinople. This was a logistical challenge, successfully completed by the disciplined Ottoman army, which used an array of oxen to pull the cannon to the front line. Operationally, firing such a large projectile produced significant recoil, as demonstrated by the momentum conservation equation. The Turkish engineers solved this problem, which remains a major consideration for Artillery engineers today, with earthen embankments, timber reinforcements, firing positions, and schedules (Agoston and Masters).
What is truly impressive about the cannon, which eventually brought down the Theodosian walls, allowing for the grand conquest, was not the fact that it could achieve such a feat, but rather the processes that went into making it possible. Orban’s expertise in metallurgy, foundry management, and thermal regulation, the Ottoman logistical and economic capabilities that facilitated this, and the vision of a Sultan who made it his mission to fulfill a prophecy are what made the Cannon possible. A grand engineering achievement that few have been able to replicate, establishing the Ottoman Empire and the legacy of Sultan Mehmed Fatih, the man who conquered the city that many dreamt of and none acquired.
References
أحمد بن محمد بن حنبل. Aḥmad Ibn Muḥammad Ibn Ḥanbal, et al. مسند الإمام أحمد بن حنبل / Musnad Al-Imām Aḥmad Ibn Ḥanbal. المكتب الاسلامى، Bayrūt, Al-Maktab Al-Islāmī, 1993.
Agoston, Gabor, and Bruce Alan Masters. Encyclopedia of the Ottoman Empire. Infobase Publishing, 1 Jan. 2009.
Crowley, Roger. “The Guns of Constantinople.” HistoryNet, 30 July 2007, historynet.com/the-guns-of-constantinople/.
Vannoccio Biringucci. The Pirotechnia of Vannoccio Biringuccio ; Translated from the Italian, with an Introduction and Notes by Cyril Stanley Smith & Martha Teach Gnudi. MIT Press, 1942.
