Scorpio (weapon)

The scorpio or scorpion was a type of Roman artillery piece. Also known by the name of the triggerfish, it was described in detail by Vitruvius. In the progressive evolution of catapults, the next major improvement after the scorpio was the cheiroballistra.

Design

See also: Ballista and Polybolos

The scorpio is a torsion catapult powered by torsion springs, a kind of ballista. It used a system of torsion springs to propel the projectiles. Scorpions could be designed to fire stones or arrow-shaped missiles of various sizes. Scorpions could be large enough to damage city walls during sieges, but the term typically refers to the smaller battlefield artillery, which were manoeuvrable enough to be taken on campaign, were light enough to be deployed in numbers on the top levels of wooden siege towers, and compact enough to be used on parapets, earthworks, and palisades. Depictions of this kind depicted are on Trajan's Column. Though the scorpion, like other ballistae, could resemble large crossbows, their design and propulsion is quite different.

The scorpio could refer to two kinds of torsion catapult; the horizontal two-armed variety like the ballistae and a one-armed, vertical version otherwise referred to as an onager. The fourth century army officer and historian Ammianus Marcellinus described the one-armed version as synonymous with the onager, with the vertical upraised arm as the 'scorpion's sting':

The scorpion, which is now-a‑days called the wild ass, has the following form. Two posts of oak or holm-oak are hewn out and slightly bent, so that they seem to stand forth like humps. These are fastened together like a sawing-machine and bored through on both sides with fairly large holes. Between them, through the holes, strong ropes are bound, holding the machine together, so that it may not fly apart. From the middle of these ropes a wooden arm rises obliquely, pointed upward like the pole of a chariot, and is twined around with cords in such a way that it can be raised higher or depressed. To the top of this arm, iron hooks are fastened, from which hangs a sling of hemp or iron. In front of the arm is placed a great cushion of hair-cloth stuffed with fine chaff, bound on with strong cords, and placed on a heap of turf or a pile of sundried bricks; for a heavy machine of this kind, if placed upon a stone wall, shatters everything beneath it by its violent concussion, rather than by its weight. Then, when there is a battle, a round stone is placed in the sling and four young men on each side turn back the bar with which the ropes are connected and bend the pole almost flat. Then finally the gunner, standing above, strikes out the pole-bolt, which holds the fastenings of the whole work, with a strong hammer, thereupon the pole is set free, and flying forward with a swift stroke, and meeting the soft hair-cloth, hurls the stone, which will crush whatever it hits. And the machine is called tormentum as all the released tension is caused by twisting (torquetur); and scorpion, because it has an upraised sting; modern times have given it the new name onager, because when wild asses are pursued by hunters, by kicking they hurl back stones to a distance, either crushing the breasts of their pursuers, or breaking the bones of their skulls and shattering them.

The complexity of construction and in particular the torsion springs (which the Romans referred to as tormenta) led to great sensitivity to any variation in temperature or moisture, which limited their use. While this type of technology continued to be used in the Byzantine Empire, which was the continuation of the Roman Empire through the Middle Ages, it had disappeared in the Middle Ages in Western Europe, but re-appeared during the First Crusade in the form of a new type of catapult based on a system of slings and counterweights for the projection of stone balls, and as giant crossbows as the field of metallurgy progressed, allowing more reliable metal tension weapons.

A modern reconstruction of the scorpio

Use

During the Roman Republic and early empire, sixty scorpions per legion was the standard, or one for every centuria. The scorpio had mainly two functions in a legion. In precision shooting, it was a weapon of marksmanship capable of cutting down any foe within a distance of 100 meters. During the siege of Avaricum in the war against the Gauls, Julius Caesar describes the terrifying precision of the scorpio. In parabolic shooting, the range is greater, with distances up to 400 meters, and the firing rate is higher (3 to 4 shots per minute). With precision shooting the rate of fire was significantly less.

Scorpions were typically used in an artillery battery at the top of a hill or other high ground, the side of which was protected by the main body of the legion. In this case, there are sixty scorpions present which can fire up to 240 bolts per minute at the enemy army. The weight and speed of a bolt was sufficient to pierce enemy shields, usually also wounding the enemy so struck.

The Scorpion was often a cumbersome and costly siege weapon, as it was quite difficult to move and acted as a more fixed weapon used for long-range defense.

Media

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  Modern reconstruction
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  Scorpio in fortified position
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  Scorpio mounted on walls
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  Dacian scorpio

In popular culture

In episode 4, season 7 of the HBO television series Game of Thrones ("The Spoils of War"), Bronn uses a fictional version of a scorpio to defend the Lannister army against an aerial assault by Daenerys Targaryen astride her largest dragon, Drogon.

A version of the "Scorpio" called the "Scorpion" is featured as a unit in the popular, critically acclaimed real-time strategy game Age of Empires II.

External links

• A Reconstruction of Vitruvius' Scorpion