Shahi Cannons

During the reign of Fatih Sultan Mehmet, the Şâhi cannons, which played a significant role in the military power of the Ottoman Empire, were large-caliber, typically bronze-cast bombard-type weapons used in 15th-century siege warfare. These cannons are particularly known for their impact in breaching the walls of Constantinople during its conquest and demonstrate the Ottoman mastery of artillery technology of the period.

Historical Context and Development

Fatih Sultan Mehmet’s reign (1451–1481) was a period during which Ottoman artillery became institutionalized and cannon-casting technology reached its peak. During this time, the Ottomans cast their first large cannons. In preparation for the conquest of Constantinople, Fatih Sultan Mehmet summoned many of the era’s foremost cannon founders to Edirne to produce cannons of various calibers. Among these masters, the most renowned was the Hungarian Urban (Orban). In addition to Urban, masters such as Ali, Müslihiddin, and Saruca were commissioned to cast the largest cannons of Fatih’s era. It is recorded that Fatih Sultan Mehmet himself possessed detailed knowledge of cannon technology and proposed a new type of cannon—similar to modern howitzers capable of high-angle fire—to target ships on the Golden Horn during the siege. The establishment of the Tophane-i Âmire during this period marked the institutionalization of Ottoman artillery.

Production and Materials

Casting Process and Foundries

The Ottomans typically carried out cannon casting in foundries characterized by square structures with roofs covered by “pedavra boards” and numerous large chimneys for smoke ventilation. The casting process took place in a large pit dug into the ground. The outer shape of the cannon was formed using a large mold made of special clay-based mud mixed with durable fibers such as linen and hemp. The internal cavity (the bore) was created using a second mold made of the same materials. Molten metal alloy was poured into the space between these two molds to form the cannon body. It is noted that the Ottomans had a thorough understanding and mastery of mold-making technology. During casting, unique rituals were performed, such as throwing gold liras into the molten alloy; it was believed that this practice strengthened the structural integrity of the cannon barrel.

One of the major casting centers during Fatih’s reign was the Demirköy/Kırklareli Facility, established to meet the army and navy’s demands for cannons, bombs, and shot. This region contained copper minerals such as chalcopyrite and bornite. The Tophane-i Âmire, depicted in miniatures by Matrakçı Nasuh, was also an important foundry building commissioned by Fatih.

Materials Used

During the reign of Fatih Sultan Mehmet, cannons were generally manufactured from bronze. Bronze consisted of approximately 90% copper and 10% tin. Although more expensive than iron, the Ottomans preferred bronze because it could be cast with thicker walls and thus withstand higher combustion pressures. Analyses of Fatih-era cannons indicate that the ideal bronze alloy was applied by the Ottomans a century before it was adopted by European states. Occasionally, substances such as zinc (spelter), lead, arsenic, antimony, and bismuth were intentionally or unintentionally added to the bronze alloy.

For cannonballs, materials such as stone, marble, lead, iron, and copper alloys were widely used. It is specified that granite cannonballs were used specifically for Urban’s cannon.

Technical Characteristics and Variants

The term “Şâhi” was used for large siege cannons, typically constructed in two parts, commissioned by Fatih Sultan Mehmet from the Hungarian master Urban and others. Although varying accounts exist regarding their dimensions, these cannons are said to have reached lengths of 8 meters, internal diameters of 80 cm, and weights of 18 tons; they could fire projectiles weighing 544–680 kg up to a distance of 2 km, with their reports of sound audible from 24 km away. It is also noted that the shortest Şâhi barrel length was 91.5 cm and its carriage weighed 8 tons.

Urban Cannon

The cannon cast by the Hungarian master Urban for Fatih Sultan Mehmet was the largest-caliber weapon used in the conquest of Constantinople.

• Dimensions: Total length of 9.2 meters, powder chamber length of 2.75 meters, and caliber (bore diameter) of 75.2 cm.
• Weight: Approximately 30,000 kg (30 tons).
• Projectile: Used granite cannonballs weighing 601 kg.
• Muzzle Velocity: Estimated at approximately 216 m/s.
• Range: Calculated to reach approximately 1464 meters when fired at a 10-degree angle. This corresponds with the distance recorded by Dukas as one Roman mile (approximately 1479 m).
• Penetration Power: Calculated to embed approximately 1.78 meters deep into earth at a distance of one mile; this aligns with Dukas’s chronicle account of one cubit (1.82 m). Analytical studies determined that the cannon could penetrate 1.16 meters into brick-and-mortar sections of the Constantinople walls and 0.475 meters into limestone layers with a single shot. Numerical analysis showed that a single shot could inflict serious damage on a tower structure and that a breach in the walls could be achieved after the second or third shot.

Dardanel Cannon (Master Münir Ali)

Approximately ten years after the conquest, in 1464, the Dardanel Cannon (known in England as the “Turkish Bombard”) was produced by Master Münir Ali and shares similar production techniques and structural characteristics with the Urban Cannon.

• Material and Construction: Cast in bronze, consisting of two parts—the barrel and the powder chamber—joined by a threaded system.
• Dimensions: Total length of 5.18 meters, powder chamber length of 2 meters, and caliber of 63 cm.
• Weight: 16,620 kg.
• Projectile: Fired cannonballs weighing 353 kg.
• Muzzle Velocity: Estimated at approximately 195 m/s.
• Casting Technique: Metallographic analysis shows that hardness values decreased toward the muzzle end, indicating that these cannons were cast vertically with the muzzle pointing downward.
• Alloy Composition: Measurements indicate that the tin content was around 8% regionally and approximately 11% overall, consistent with 15th-century bronze cannons.

Design Features

The two-part casting of large siege cannons—such as the Urban and Dardanel cannons—followed by threaded assembly was a significant technological innovation developed to facilitate transportation of these massive weapons.

Other Cannon Types

During Fatih’s reign and afterward, the Ottomans also employed various other types of cannons known by names such as Balyemez, Darbzen (wall-smashing cannon), and Humbara (a type of hand grenade).

Operational Characteristics

Firing and Usage

These large cannons were muzzle-loaded: gunpowder and projectiles were inserted through the barrel, and ignition was performed through a small channel known as the “falya deliği.” Kritovulos noted that the powder chamber of Urban’s cannon was completely filled and compacted with gunpowder.

Firing Rate and Cooling

The firing rate of large cannons was low. Dukas recorded that during the siege, Urban’s cannon could fire between three and seven times per day, and that it was cooled with olive oil between shots to prevent cracking. It is noted that the practice of cooling heated firearms with oil was first implemented by the Ottomans during this period.

Logistics

The transportation of Urban’s massive cannon required a major logistical operation. Historical records indicate that the cannon departed from Edirne in late January 1452 and arrived before Constantinople only two months later. According to some historians, it was pulled by 30 carts and 140 oxen (other sources mention 50–60 pairs of oxen), and 200 soldiers were assigned to prevent it from overturning. This highlights the logistical constraints of transporting large cannons. The two-part design aimed to alleviate some of these transport difficulties.

Role and Impact in the Siege

Urban’s cannon was one of the decisive factors in the conquest of Constantinople, creating both physical damage to the walls and a psychological collapse among the defenders due to the immense explosive force of its discharge. It is recorded that Fatih Sultan Mehmet specifically positioned Urban’s cannon at the point on the Constantinople walls where the brickwork was thinnest. Multiple shots directed at the same target area, or arranged in a triangular formation as advised by the envoy of John Hunyadi, are said to have caused the collapse of the fortress walls.

Innovations and Comparisons

Ottoman Innovations

The reign of Fatih Sultan Mehmet witnessed significant innovations in Ottoman artillery:

• Movable Cannon Foundries: The concept of mobile cannon foundries, a notable development in the history of artillery worldwide, was realized during this period.
• Two-Part Large Siege Cannons: The two-part design facilitating easier transport was a major innovation.
• Advanced Mold Technology: The Ottomans are shown to have effectively utilized mold-making technology.
• Bronze Alloy Composition: Evaluations indicate that the ideal bronze alloy was applied by the Ottomans a century before its adoption in Europe.
• Oil Cooling: The practice of cooling firearms with oil began during this period.

Comparison with Contemporary European Cannons

In Ahmet Kaan Toksoy’s study, Urban’s cannon and its contemporaries were compared:

• Production Material and Technique: While large cannons produced in 15th-century Europe were generally forged from iron, the Ottomans preferred bronze despite its higher cost. Unlike European cannons, which were cast as single pieces or assembled using different joining methods, the large Ottoman cannons such as Urban’s and Dardanel’s were produced using two-part casting and threaded assembly.
• Metallurgy: Metallographic analysis revealed that the Dardanel Cannon was cast vertically with the muzzle pointing downward, and its hardness values were comparable to those of other cannons of the period. Toksoy concludes that while there was no overall metallurgical superiority in 15th-century Ottoman artillery technology, the production technique of the Urban and Dardanel cannons was distinct. In contrast, Fevzi Yılmaz asserts that the ideal bronze alloy used by the Ottomans was applied a century before its adoption in Europe.
• Ballistic Performance: In terms of internal ballistics, some European cannons demonstrated superior range and muzzle velocity. However, Urban’s cannon possessed the highest total kinetic energy among its contemporaries due to the size and weight of its 601 kg granite projectile, making it the most effective weapon for damaging the walls. Although its range and muzzle velocity were lower than those of some contemporaries, its projectile’s diameter and mass enabled it to inflict the most effective damage on the Constantinople walls; calculations show that its contemporaries lacked this capacity.

Surviving Examples

Six cannons produced in various calibers during the reign of Fatih Sultan Mehmet have survived to the present day.

Dardanel Cannon (Anadolu Agency)

• Dardanel Cannon (Master Münir Ali, 1464): The best-known of these cannons is displayed at the Fort Nelson Museum in Portsmouth, England (part of the Royal Armouries collection). This cannon was presented by Sultan Abdülaziz to Queen Victoria in 1868 as a gift commemorating his visit to England. The cannon bears an engraved inscription by Münir Ali, dated Recep 868 AH (1464 CE), offering prayers for Sultan Mehmet, son of Sultan Murat, along with decorative motifs. The cannon was used in 1807 against British ships attempting to pass through the Dardanelles.
• Others: Of the other five surviving cannons, four are located in Istanbul, and one is housed in the National Historical Artillery Museum (Museo Storico Nazionale di Artiglieria) in Taranto, Italy. The cannon displayed at the entrance of the Istanbul Military Museum, from the conquest period, was manufactured as a single-piece casting, weighing 15 tons, measuring 424 cm in length, and having an external diameter of 63 cm.

At the ALUTEAM CAD/CAM and Additive Manufacturing Laboratory of Fatih Sultan Mehmet University, 1/25 and 1/50 scale models of the two-part, threaded Şâhi cannon (crafted by Münir Ali) from the Fort Nelson Museum have been produced using laser technology with polystyrene powder.