Ottoman Gunpowder Siege Warfare

Ottoman military expansion in the fifteenth and sixteenth centuries rested, to a remarkable degree, on the conduct of sieges. From the conquest of Bursa in 1326 to the long contest for Vienna in 1683, the principal moments of Ottoman military history are moments at which an Ottoman army, supported by a powerful artillery train, hammered at the walls of a great city. The Ottomans were among the earliest and most aggressive adopters of gunpowder weapons, and the institutional apparatus they built around siege warfare — the topçu ocak, the imperial arsenal, the corps of master bombardiers, the sappers and miners — is one of the most distinctive features of their military.

A general account of the Ottoman military is given in the article on Ottoman military and warfare, and the most celebrated sieges — Malta in 1565 and Vienna in 1529 and 1683 — are treated in their own dedicated articles on the Great Siege of Malta and the siege of Vienna. This article focuses on the technical, institutional, and tactical history of Ottoman siege warfare in the period of the great bombards.

The early adoption of gunpowder

The Ottoman use of cannon at the siege of Bursa in 1326 is among the earliest securely dated deployments of artillery in the Islamic world. By the 1380s, the Ottomans were casting cannon in significant numbers, and the chronicles of the late fourteenth century contain regular references to the use of bombards and smaller pieces. The early Ottoman cannon were cast in bronze, often in the workshops of the great cities of Anatolia, and they followed Byzantine and European models.

The decisive moment in the early history of Ottoman siege warfare came in 1453, when Mehmed II assembled a siege train that included several very large bombards, including the famous Dardanelles gun of the Hungarian-born engineer Orban. The bombards cast by Orban for the 1453 campaign were among the largest in the world at the time, and the damage they did to the walls of Constantinople is recorded in detail by the chronicler Kritoboulos of Imbros. The fall of Constantinople on 29 May 1453 made the new technology famous and gave the Ottomans a decisive advantage in the wars that followed.

The topçu ocak and the imperial arsenal

By the reign of Bayezid II (r. 1481-1512), the Ottoman artillery was organised into a permanent corps, the topçu ocak, with its own officers, training establishments, and arsenals. The corps was responsible for the casting, transport, and operation of cannon, and it provided the technical cadre for the great siege trains of the sixteenth century.

The chief engineer of the corps held the title of topçu başı and reported to the Kapudan Pasha of the arsenal in Istanbul. The corps included master bombardiers (ustad topçu), gun-crew commanders, sappers, miners, and a long list of auxiliary and technical specialists. The training of the topçu ocak was theoretical as well as practical: Ottoman engineers produced a substantial body of treatises on ballistics, on the construction of fortifications, and on the conduct of sieges, drawing on Greek, Arabic, and Italian sources. The work of Taqi al-Din, the Ottoman astronomer and engineer who served in the court of Murad III, is part of the same intellectual tradition.

The great bombards

The most distinctive weapon of the Ottoman siege train in the fifteenth and sixteenth centuries was the very large bombard, cast in bronze and mounted on a heavy wooden bed. The Dardanelles gun, cast in 1464 for the campaign against the emirate of Karaman, fired a stone ball of more than 300 kilograms; the famous Basilica gun of Mehmed II, cast in 1453, was used in the same year against the walls of Constantinople; the guns cast for the siege of Rhodes in 1522 included several pieces of comparable size.

These very large bombards were difficult to transport, slow to load, and prone to crack under the strain of repeated firing. They were, in a sense, more impressive as instruments of terror than as practical siege weapons, and a single gun might fire only a dozen or so effective shots in a campaign. The bulk of the practical work of an Ottoman siege was done by medium and light guns: the darbzen, the şayka, the kolomborna, and the various smaller pieces of the train.

Conduct of a siege

A typical Ottoman siege combined several methods. Heavy artillery battered the walls from a distance, throwing stone or, increasingly, iron shot; lighter guns swept the ramparts at close range; sappers worked their way forward, under cover of mantlets, to mine the foundations; and, in the final assault, massed Janissaries and assault troops attempted to storm the breaches. The technical level of Ottoman mining and countermining was high, and the besiegers and the defenders often fought a long underground battle for control of the mines.

The logistics of a major siege were formidable. The Ottoman army of Suleiman’s reign could field tens of thousands of men, hundreds of wagons, and large herds of livestock, supported by a chain of supply depots and bridgeheads. The siege of a major city might last for months: the siege of Rhodes in 1522 lasted six months, the first siege of Vienna in 1529 lasted nearly three weeks of active bombardment, the Great Siege of Malta lasted four months, and the second siege of Vienna in 1683 lasted two months. The Ottoman army was an army of movement and of patient siege craft.

The great sieges of the fifteenth and sixteenth centuries

The five most celebrated Ottoman sieges of the period are Constantinople (1453), Belgrade (1521), Rhodes (1522), the first siege of Vienna (1529), and the Great Siege of Malta (1565). Each of these operations is treated in detail in its own article, and only a few general points can be made here.

Constantinople (1453) is the iconic case. The city had not fallen to an army in seven hundred years, and the technical resources that Mehmed II brought to the siege — the great bombards, the fleet, the pontoon bridge across the Golden Horn — are some of the most famous in military history. The fall of the city, on 29 May 1453, transformed the eastern Mediterranean. Belgrade (1521) and Rhodes (1522) opened the way for the campaign of Mohács and the long struggle with the Habsburgs. The first siege of Vienna (1529) reached the walls of the Habsburg capital and was repulsed by the garrison. Malta (1565) is the most celebrated of the late sixteenth-century sieges.

A few further operations are worth mentioning for the light they cast on Ottoman siege warfare. The siege of Famagusta in Cyprus, in 1570-71, was a smaller operation than the great continental sieges, but the surrender of the Venetian garrison, on terms, was followed by the brutal execution of the defenders — a violation of the terms of surrender that became a European cause célèbre. The campaign of Tunis in 1535, in which the Emperor Charles V took the city from the corsair Barbarossa ally Hasy al-Din, is a striking example of an early modern Christian counter-siege. The long Venetian-Ottoman war over Crete (1645-1669) involved a series of sieges around Candia (Heraklion), in which the Ottoman army was finally successful after a 21-year campaign. The siege of Candia is one of the longest in Ottoman military history, and it is a useful case study of the long, patient siege tradition of the empire.

Fortification and counter-siege

The Ottoman success in siege warfare was, in part, a response to the development of European fortification. The trace italienne, the low, thick-walled, angular fortress designed to absorb cannon fire, was developed in Italy in the late fifteenth century and rapidly spread to the rest of Europe. The Ottomans adopted the new form in their own fortifications, especially in the Balkans and along the Persian frontier, and the late sixteenth and seventeenth century saw a long contest between Ottoman gunnery and the new European style of defence.

The successful defence of Malta in 1565, of Vienna in 1683, and of several other great fortresses against the Ottomans is in part a result of the technical superiority of the trace italienne over the older high-walled fortress of the medieval type. The same period saw the development of the bastion and the ravelin, the angular outwork designed to sweep the ditch and the wall, and the Ottoman engineering corps was quick to study and to adopt the new forms.

The new fortification also required a new approach to the siege. The high medieval wall, designed to withstand the medieval trebuchet, was vulnerable to the heavy siege gun; the low, thick, angular bastion was designed to absorb the impact and to deny the besiegers a target. The Ottoman response was twofold. On the one hand, the topçu ocak developed lighter, more mobile field pieces that could be moved to keep pace with the changing pattern of the siege; on the other hand, the engineers of the corps developed new methods of mining, sapping, and assault, suited to the new form of fortification. The exchange between attack and defence is one of the most striking features of late sixteenth and seventeenth-century military history, and the Ottoman contribution to that exchange is one of the most distinctive elements of the period.

The sieges were conducted by the Janissary corps and the sipahi levies, supported by the great siege train and by the Ottoman fleet where the campaign was amphibious. The Janissary was the principal storm troop of the corps, and the corps had a long and successful tradition of siege warfare. The fleet provided the logistical support for the great campaigns, and the operation of Malta in 1565 is one of the best examples of the joint operation of army and navy.

Decline

The seventeenth century saw a slow relative decline of Ottoman siege warfare. The cost of the great siege train was high, the Habsburg and Russian armies were increasingly well-equipped and well-led, and the Ottoman army suffered a series of heavy defeats in the wars around Hungary and the Black Sea. The second siege of Vienna in 1683, in which the Ottoman army was decisively defeated by the Polish relief force under King John III Sobieski, is the conventional end of the great period of Ottoman siege warfare.

The eighteenth and nineteenth centuries saw the gradual modernisation of the Ottoman artillery, the adoption of European-style field artillery, and the eventual obsolescence of the great bombards. The topçu ocak was reorganised in the nineteenth century, and the corps of engineers was reformed in the late Ottoman period. The tradition of the great bombards, however, remained a powerful element of Ottoman military memory, and the surviving examples of the guns of Mehmed II, of Suleiman, and of later sultans are still preserved in the collections of the Istanbul military museums.

Ottoman military and warfare — A general account of the Ottoman military, of which siege warfare was a central element.
The Janissary corps — The elite infantry that stormed the breaches and held the lines in the great Ottoman sieges.
The Ottoman navy — The fleet that carried the siege trains across the Mediterranean and supported the great amphibious operations.
The Great Siege of Malta — The 1565 siege of Malta by Suleiman’s army, one of the most celebrated sieges of the period.
The siege of Vienna — The 1529 and 1683 sieges that bookend the great period of Ottoman expansion into central Europe.