Greek artillery tower equipped with torsion ballistas Preceding the development of torsion siege engines were tension siege engines that had existed since at least the beginning of the 4th century BC, most notably the
gastraphetes in
Heron of Alexandria's Belopoeica that was probably invented in
Syracuse by
Dionysius the Elder. Though simple torsion devices could have been developed earlier, the first extant evidence of a torsion siege engine comes from the Chalcotheca, the arsenal on the
Acropolis in
Athens, and dates to c. 338 - 326 BC. It lists the building's inventory that included torsion catapults and its components such as hair springs, catapult bases, and bolts. The transition from tension machines to torsion machines is a mystery, though E.W. Marsden speculates that a reasonable transition would involve the recognition of the properties of sinew in previously existing tension devices and other bows. Torsion based weaponry offered much greater efficiency over tension based weaponry. Traditional historiography puts the speculative date of the invention of two-armed torsion machines during the reign of Philip II of Macedon circa 340 BC, which is not unreasonable given the earliest surviving evidence of siege engines stated above. The machines quickly spread throughout the ancient Mediterranean, with schools and contests emerging at the end of the 4th century BC that promoted the refinement of machine design. They were so popular in ancient Greece and Rome that competitions were often held. Students from
Samos,
Ceos,
Cyanae, and especially
Rhodes were highly sought after by military leaders for their catapult construction. Torsion machines in particular were used heavily in military campaigns.
Philip V of Macedon, for example, used torsion engines during his campaigns in 219-218 BC, including 150 sharp-throwers and 25 stone-throwers.
Scipio Africanus confiscated 120 large catapults, 281 small catapults, 75 ballistas, and a great number of
scorpions after he captured
New Carthage in 209 BC.
Roman on
Trajan's Column The Romans obtained their knowledge of artillery from the Greeks. In ancient Roman tradition, women were supposed to have given up their hair for use in catapults, which has a later example in
Carthage in 148-146 BC. Torsion artillery, especially ballistas came into heavy usage during the
First Punic War and was so common by the
Second Punic War that
Plautus remarked in the
Captivi that “Meus est ballista pugnus, cubitus catapulta est mihi” (“The ballista is my fist, the catapult is my elbow"). By 100 AD, the Romans had begun to permanently mount artillery, whereas previously machines had traveled largely disassembled in carts. Romans made the Greek ballista more portable, calling the hand-held version
manuballista and the cart-mounted type
carroballista. They also made use of a one armed torsion stone-projector named the
onager. The earliest extant evidence of the carroballista is on
Trajan's Column. Between 100 and 300 AD, every
Roman legion had a battery of ten onagers and 55 cheiroballistas hauled by teams of mules. After this, there were legionaries called
ballistarii whose exclusive purpose was to produce, move, and maintain catapults. In later antiquity the
onager began to replace the more complicated two-armed devices. The Greeks and Romans, with advanced methods of military supply and armament, were able to readily produce the many pieces needed to build a ballista. In the later 4th and 5th centuries as these administrative structures began to change, simpler devices became preferable because the technical skills needed to produce more complex machines were no longer as common.
Vegetius,
Ammianus Marcellinus, and the anonymous "
De rebus bellicis" are our first and most descriptive sources on torsion machines, all writing in the 4th century AD. A little later, in the 6th century,
Procopius provides his description of torsion devices. All use the term ballistas and provide descriptions similar to those of their predecessors.
Medieval continuity (4th-6th century torsion weapon) - the sling version improved on the bucket by increasing arm length without burdening the arm with extra weight A common misconception about torsion siege engines such as the
ballista or
onager is their continued usage after the beginning of the
Early Middle Ages (late 5th-10th centuries AD). These artillery weapons were only used in the West until the 6-8th centuries, when they were replaced by the traction trebuchet, more commonly known as the
mangonel. The myth of the torsion mangonel began in the 18th century when
Francis Grose claimed that the onager was the dominant medieval artillery until the arrival of gunpowder. In the mid-19th century,
Guillaume Henri Dufour adjusted this framework by arguing that onagers went out of use in medieval times, but were directly replaced by the counterweight trebuchet. Dufour and
Louis-Napoléon Bonaparte argued that torsion machines were abandoned because the requisite supplies needed to build the sinew
skein and metal support pieces were too difficult to obtain in comparison to the materials needed for tension and counterweight machines. In the early 20th century,
Sir Ralph Payne-Gallwey concurred that torsion catapults were not used in medieval times, but only owing to their greater complexity, and believed that they were superior to "such a clumsy engine as the medieval trebuchet." Others such as General Köhler disagreed and argued that torsion machines were used throughout the Middle Ages. The torsion mangonel myth is particularly appealing for many historians due to its potential as an argument for the continuity of classical technologies and scientific knowledge into the Early Middle Ages, which they use to refute the concept of medieval decline. It was only in 1910 that Rudolph Schneider pointed out that
medieval Latin texts are completely devoid of any description of the torsion mechanism. He proposed that all medieval terms for artillery actually referred to the trebuchet, and that the knowledge to build torsion engines had been lost since classical times. In 1941, Kalervo Huuri argued that the onager remained in use in the Mediterranean region, but not ballistas, until the 7th century when "its employment became obscured in the terminology as the traction trebuchet came into use." Some historians such as Randall Rogers and Bernard Bachrach have argued that the lack of evidence regarding torsion siege engines does not provide enough proof that they were not used, considering that the narrative accounts of these machines almost always do not provide enough information to definitively identify the type of device being described, even with illustrations. However, by the 9th century, when the first Western European reference to a
mangana (mangonel) appeared, there is virtually no evidence at all, whether textual or artistic, of torsion engines used in warfare. The last historical texts specifying a torsion engine, aside from bolt throwers such as the springald, date no later than the 6th century. Illustrations of an onager do not reappear until the 15th century. With the exception of bolt throwers such as the
springald which saw action from the 13th to 14th centuries or the
ziyar in the Muslim world, torsion machines had largely disappeared by the 6th century and were replaced by the
traction trebuchet. This does not mean torsion machines were completely forgotten since classical texts describing them were circulated in medieval times. For example,
Geoffrey Plantagenet, Count of Anjou had a copy of
Vegetius at the siege of Montreuil-Bellay in 1147, yet judging from the description of the siege, the weapon they used was a traction trebuchet rather than a torsion catapult. Contributing to the torsion mangonel myth is the muddled usage of the term
mangonel.
Mangonel was used as a general medieval catch-all for stone throwing artillery, which probably meant a
traction trebuchet from the 6th to 12th centuries, between the disappearance of the onager and the arrival of the counterweight trebuchet. However many historians have argued for the continued use of onagers into medieval times by wading into terminological thickets. For example, at the end of the 19th century, Gustav Köhler contended that the
petrary was a traction trebuchet, invented by
Muslims, whereas the mangonel was a torsion catapult. Even disregarding definition, sometimes when the original source specifically used the word "mangonel," it was translated as a torsion weapon such as the ballista instead, which was the case with an 1866 Latin translation of a Welsh text. This further adds to the confusion in terminology since "ballista" was used in medieval times as well, but probably only as a general term for stone throwing machines. For example
Otto of Freising referred to the mangonel as a type of ballista, by which he meant they both threw stones. There are also references to Arabs, Saxons, and Franks using ballistas but it is never specified whether or not these were torsion machines. It is stated that during the siege of
Paris in 885–886, when
Rollo pitted his forces against
Charles the Fat, seven Danes were impaled at once with a bolt from a
funda. Even in this instance it is never stated that the machine was torsion, as was the case with uses of other terminology such as
mangana by
William of Tyre and
Willam the Breton, used to indicate small stone-throwing engines, or "cum cornu" ("with horns") in 1143 by
Jacques de Vitry. In modern times the mangonel is often confused with the onager due to the torsion mangonel myth. Modern military historians came up with the term "traction trebuchet" to distinguish it from previous torsion machines such as the onager. However
traction trebuchet is a newer modern term that is not found in contemporary sources, which can lead to further confusion. For some, the mangonel is not a specific type of siege weapon but a general term for any pre-cannon stone throwing artillery. Onagers have been called onager mangonels and traction trebuchets called "beam-sling mangonel machines". From a practical perspective, mangonel has been used to describe anything from a torsion engine like the onager, to a traction trebuchet, to a counterweight trebuchet depending on the user's bias. ==Construction==