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By Fra' Tom Morin, CPT, FA, USA

Artillery of the Military Orders

                Sieges were an instrumental part of medieval warfare. While large pitched battles were quite rare, sieges were commonplace. As a result, medieval commanders devoted a lot of brainpower to sieges, and a plethora of ingenious weapons were designed to assist in reducing enemy strongholds. Essential to that task were weapons which could shoot large projectiles to batter down enemy fortifications, and bring a castle’s garrison to its knees. Here we will discuss the various types of artillery that were available to the crusading military orders from the 12th century until the beginning of the 16th century.




                Although medievals had no formal knowledge of physics, nor computers to assist them with advanced calculations, it would be a mistake to think of siege weapons as simplistic. Like most types of military equipment today, the machines were usually kept as simple as possible in order that they might be easy to operate and use, but they still required some advanced knowledge to construct them. It is perhaps for this reason that clerics are often found in close association with siege machines. During the Albigensian Crusade, Simon de Montfort’s largest trebuchet at the siege of Penne d’Agenais was designed by the archdeacon of Paris. This sort of thing was likely more common during crusades, where church clerics would have held leadership positions and also had the requisite knowledge of mathematics and engineering to accomplish the building of such weapons. Military orders typically had chaplain-brothers who accompanied them on campaigns who were educated, and may have been able to provide such expert knowledge to crusading armies and assist in the design and construction of artillery weapons with which to fight the Muslims.

                Siege weapons were very expensive, and usually only the richest and most powerful military commanders could afford them. Engineers were rare and typically paid very well, their salaries often appearing on royal accounts from the period. Sometimes the weapons could be assembled on the spot from felled trees or by repurposing the wood from ships. Often, however, siege weapons were constructed beforehand and then disassembled and loaded into carts, in order to be reassembled once the army had arrived before the castle. Sailors, who were used to working with wood, were often put to work building siege weapons, as at the siege of Jerusalem when Genoese sailors helped smooth out the beams and fit them together to build the Belfry used by Godfrey of Bouillon. Though the military orders never had the manpower to carry out large military operations on their own, there are references in early sources of their own siege weapons that accompanied the armies of larger crusading forces, such as at the siege of Acre in 1191, where both the Hospitallers and Templars each had their own catapult.




           Just as they are nowadays, medieval artillery weapons were employed in groups called ‘batteries.’ This was done in order to mass firepower on a particular weak spot in the castle defenses, and also to permit more constant bombardment. It is not uncommon to find descriptions in sources from the period of bombardments lasting all day and night, such as James I of Aragon’s artillery at the siege of Lisana, which was said to throw a combined 500 stones at night, and some 1,000 during the day. Siege weapons seemed to proliferate from the 13th century onward, such that the eighteen catapults Saint Louis used during the Mansourah campaign in Egypt need not be considered a particularly large amount.

                The types of missiles used by medieval machinery varied greatly. Some hurled stones upwards of 300lbs, or fired bolts that could impale five men at a time, such as the ballista employed by the French against the Vikings during the siege of Paris in 885. Like ships, large siege weapons were often given their own names that were meant to spread fear among their enemies, such as ‘Malregard,’ ‘Warwolf,’ or ‘The Chorosan Crusher.’ But siege weapons didn’t just hurl stones, metal ammunition such as lead balls were sometimes made for the purpose of using as projectiles, as well as clay pots filled with Greek fire, which was a favorite weapon of the Muslims. Really, any sort of heavy object would do, and there are plenty of examples in which dead animals, dung, beehives, or even live enemy prisoners were used.


Types of Medieval Artillery




Other names: Catapult, Tormentum


                The ballista and its very similar counterpart, the catapult, have been in existence since Roman times. This machine was similar in design to the crossbow, and was typically used to fire large, arrow-like bolts that could impale multiple men with a single shot. The weapon was operated by using a large crank to pull back the string so that the missile could be placed in the groove. Some machines used a system of twisted ropes to create torsion, though there is some evidence that this style fell out of popularity in the Middle Ages. These machines had a range of 100-200 yards, depending on the trajectory and the size of the projectile. Ballistas could be built on swivels like those Saint Louis used at Mansourah, and they were very accurate. There are many examples which seem to indicate the frightening precision of these machines, such as the unfortunate Anselm de Ribaut, who was hit in the head by a tormentum at the Siege of Arqah, or Simon de Montfort, who was killed by a projectile fired by a machine operated by the “ladies and girls of Toulouse.” Crusaders at Tyre employed a particular Armenian for his skill at hitting selected targets with a ballista.




Other names: Petrary


                The word ‘mangonel’ is a diminutive form, which seems to indicate a smaller sort of machine, with ‘petrary’ sometimes being used to denote a similar, though larger weapon. However, medieval chroniclers are frustratingly imprecise in their use of words to describe siege weapons, so it is difficult to know for sure. The machine most often described as a mangonel or petrary possessed a long arm with a cup at the end. The arm was pulled back either by cranks or by manpower, then secured with twisted ropes to provide torsion. Once ammunition was placed into the cup, the arm could be released. The arm would smack into a cross-beam and release the ammunition, throwing projectiles at a distance of over 300ft.  Range and trajectory on a mangonel could be altered by adjusting the length of the arm or the position of the crossbeam, though many details about precise construction of these machines are unknown due to secrecy maintained by medievals surrounding their operation.

                Mangonels are a very old weapon, and can be found among the arsenals of the ancient Greeks and Romans. It was perhaps the most reliable artillery weapon, and was a particular favorite of the Turks, who used mangonels even as late as the siege of the Hospitaller’s castle on Rhodes in 1480 to hurl clay eggs called ‘carcasses’ which contained a flammable mixture that burst upon impact. Though they were not as powerful as their later cousin, the trebuchet, they still packed enough of a punch to do significant damage to castle walls, such as at the siege of Tortona in 1155, where Frederick I of Germany’s mangonel broke apart a tower, killing three unfortunate knights standing below.




Other names: Funda


         The trebuchet was the pinnacle of artillery technology before the introduction of gunpowder. There were two types of trebuchet, a Traction Trebuchet which operated by pulling ropes tied to one end, and the more well-known version which operated with the use of a counterweight. It was the largest of the hurling machines, and represented a significant leap in artillery technology. Essential to the operation of a trebuchet was the use of a pivot, indeed the word ‘trebuchet’ derives from an ancient word for a balance.

         A typical trebuchet possessed a large beam on a pivot, where the pivot was closer to one end to create imbalance. On a counterweight trebuchet, a large container filled with rocks or earth was attached to the shorter end of the beam, while a sling inside of which the ammunition was loaded was attached to the other end. The longer end was then winched down and held in position by a catch. By releasing the catch, gravity would cause the shorter end to drop and propel the longer end into the air. One end of the sling would then come loose and launch the projectile toward its target.

       The range and rate of fire advantages of the trebuchet over other types of hurling weapons were significant. Counterweight trebuchets could launch 200-300lb projectiles over 300 yards. They could also fire very rapidly, able to be reloaded in a matter of minutes, as is implied by the near-constant bombardment suffered at the siege of Lisbon in 1147. Trebuchets could also be very accurate. A Danish crew that reconstructed a medieval trebuchet in 1989 demonstrated that their machine was not only reliable, but nearly as accurate as a modern-day mortar.

       The origins and first use of the trebuchet is subject of much debate, but it is generally accepted that these weapons were relatively common in Europe by the 13th century. Traction trebuchets were certainly in existence much earlier, and some of the machines used by the first crusaders at Nicaea and Jerusalem match the description of a traction trebuchet. Other descriptions of machines with the appearance of long-hair date from as early as the 11th and 12th centuries.




Other forms: Bombard, Mortar, Basilisk, Culverin, Serpentine


                Though it was slow to start, and the first models used in the 14th century proved somewhat ineffective, eventually the cannon would replace all other artillery weapons. Medieval cannons were constructed either of strips of forged iron beaten together, or in later times molded into a solid piece. They were typically breech-loaded--meaning loaded from the rear--by use of a mobile chamber, called a ‘thunder-box’ which was placed into the breech and secured with an iron rod. Between the powder and the ammunition, a wooden plug made from “good dry alder or willow wood” was placed in order to create a good seal to trap the gasses from igniting the powder. The powder was igniting by use of a touch-hole. Once pressure had built sufficiently, the wooden plug would pop like a champagne cork, propelling the projectile out with incredible force and speed.

                Unlike modern gunpowder, the mixture used by medievals was much less combustible, and did not ignite instantaneously like a modern or Napoleonic-era cannon. The combustion was much slower, and the cannon’s operation relied heavily on keeping the gasses trapped inside the chamber until enough pressure built up, hence why a wooden plug was necessary in these types of cannons. Heat would cause the wood to expand enough to form a firm seal and build up pressure behind it.

                Most medieval cannons were relatively small, 8-10 feet in length, and fired lead, iron, or stone balls weighing roughly 15-20lbs. There were plenty of large cannons, however, and some bombards could fire projectiles of over 300lbs. The great Turkish bombard Mons Meg ordered by Philip the Good of Burgundy in 1449 could fire stone projectiles in excess of 549 lbs. Cannons such as these were typically aimed by mounting or tying them to a wooden board, using wooden wedges to adjust the angle vertically. By the mid-15th century, most smaller cannons were mounted on two-wheeled carriages much like later Napoleonic-style cannon.

                Though they remained rare throughout the 14th century, cannons became a common sight on medieval battlefields by the middle of the 15th century, and by the mid-16th century they had replaced nearly every other type of artillery weapon. The Knights Hospitaller enthusiastically adopted the cannon in the 15th century for use against the Turks, and demonstrated its effectiveness at sea while conducting naval operations in the Mediterranean. By 1480, the Hospitallers had expanded the duties of the Turcopolier to include overseeing of coastal defenses, which presumably made him primarily responsible for the defensive artillery and cannon utilized by the Order.



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  2. Bennet, Matthew, Jim Bradbury, Kelly Devries, Iain Dickie, and Phyllis JesticeFighting Techniques of the Medieval World 500-1500: Equipment, Combat Skills, and Tactics. New York, NY: Amber Books, 2005.

  3. Bradbury, Jim. The Medieval Siege. Woodbridge: Boydell Press, 1992.

  4. Contamine, Philippe. War in the Middle Ages. Translated by Michael Jones. Paris: Presses Universitaires de France, 1984.

  5. Joinville, Jean. The Life of Saint Louis. Translated by Margaret Shaw. London: Penguin Books, 1963.

  6. Krahenbuhl, Kevin. "The Albigensian Crusade: A twist in the story of the Crusades." Medieval Warfare, 6-10.

  7. Nicolle, David. Knights of Jerusalem: The Crusading order of Hospitallers 1100-1565. New York, NY: Osprey Publishing, 2008.

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