Ballista

Also: ballistae, scorpio, torsion artillery, Roman artillery

Greek and Roman torsion artillery that threw bolts or stones with the force of twisted sinew rope, explained here by the wounds it left in the people it hit.

Questions this entry answers

  • How did a Roman ballista work?
  • What kind of wounds did a ballista cause?
  • What is the difference between a ballista and a catapult?

Definition

A ballista was a piece of ancient artillery powered by torsion. Two wooden arms were set into tightly twisted skeins of sinew or hair rope. Drawn back with a winch and released, the arms drove a bowstring forward and threw a bolt or a stone.

Historical context

Torsion artillery developed in the Greek world in the fourth century BC, and Rome took it up. The names shifted over time. In earlier Roman usage catapulta often meant a bolt-shooter and ballista a stone-thrower; by late antiquity ballista usually meant a bolt-shooter. Small bolt-shooters were called scorpiones. The architect Vitruvius, writing under Augustus, gave construction details in Book X of De Architectura.

Roman armies took artillery on campaign. Trajan's Column shows bolt-shooters mounted on carts.

How it worked

  1. Power. Twisting the skeins stored energy. The tighter and more even the tension on both sides, the more force at release.
  2. Loading. The crew winched the slider back, locked it with a trigger, and set the missile in the groove.
  3. Release. The arms swung forward and threw the bolt or stone along the line of the stock.

A bolt-shooter could be aimed at a single person at long range. Stone-throwers were used mostly against walls, gates and the people behind them.

What it meant for the patient, the soldier, the civilian

An iron-headed bolt could pass through a shield and the body behind it. A thrown stone crushed. The person struck often never saw the machine that hit them.

A bolt lodged in the body had to come out. Celsus gives a section of De Medicina to removing weapons from the body without causing more harm, which could mean widening the wound or pushing the point on through. There was no reliable anaesthesia; the patient was held still. If they survived the extraction, bleeding, infection or a damaged limb could still follow.

Examples from history

  • Maiden Castle, Dorset. A skeleton from the hillfort's cemetery has an iron bolt head lodged in a vertebra. It has long been read as a casualty of Roman artillery during the conquest of Britain in the AD 40s. Later work has re-examined the dating and context of the burials, so the identification is best treated as probable, not settled.

Sources

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Primary source

  1. Vitruvius. On Architecture, Book X. Trans. Frank Granger. Loeb Classical Library, 2 vols. Harvard University Press, 1931–1934.

    Not yet checked against the source

  2. Celsus. De Medicina. Trans. W. G. Spencer. Loeb Classical Library, 3 vols. Harvard University Press, 1935–1938.

    Removal of weapons from the body, Book VII (cited in the Rome research notes as 7.5).

    Not yet checked against the source

Scholarly secondary source

  1. Marsden, E. W. Greek and Roman Artillery. Historical Development. Clarendon Press, 1969.

    Not yet checked against the source

  2. Marsden, E. W. Greek and Roman Artillery. Technical Treatises. Clarendon Press, 1971.

    Not yet checked against the source

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