Catapult Definition, History, and Types

Some types and history of the Roman weapon

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Descriptions of Roman sieges of fortified cities invariably feature siege engines, the most familiar of which are the battering ram or aries, which came first, and the catapult (catapulta, in Latin). Here is an example from the first century A.D. Jewish historian Josephus on the siege of Jerusalem:

"2. As for what is within the camp, it is set apart for tents, but the outward circumference hath the resemblance to a wall, and is adorned with towers at equal distances, where ​between the towers stand the engines for throwing arrows and darts, and for slinging stones, and where they lay all other engines that can annoy the enemy, all ready for their several operations."
Josephus Wars. III.5.2
[Read more from ancient authors Ammianus Marcellinus (fourth century A.D.), Julius Caesar (100-44 B.C.), and Vitruvius (fl. first century B.C.) at the end of this article.]

According to "Recent Finds of Ancient Artillery," by Dietwulf Baatz, the most important sources of information on ancient siege engines come from ancient texts written by Vitruvius, Philo of Byzantium (third century B.C.) and Hero of Alexandria (first century A.D.), relief sculptures representing sieges, and artifacts found by archaeologists.

The Meaning of the Word Catapult

Etymology Online says the word catapult comes from the Greek words kata 'against' and pallein 'to hurl,' an etymology that explains the working of the weapon, since the catapult is an ancient version of the cannon.

When Did the Romans Start to Use the Catapult?

When the Romans first started using this type of weapon isn't known with certainty. It may have begun after the Wars with Pyrrhus (280-275 B.C.), during which the Romans had an opportunity to observe and copy Greek techniques. Valérie Benvenuti argues that the inclusion of towers within Roman-built city walls from about 273 B.C.

suggests that they were designed to hold siege engines.

Early Developments in the Catapult

In "Early Artillery Towers: Messenia, Boiotia, Attica, Megarid," Josiah Ober says the weapon was invented in 399 B.C. by engineers in the employ of Dionysios of Syracuse. [See Diodorus Siculus 14.42.1.] Syracuse, in Sicily, was important to Megale Hellas, the Greek-speaking area in and around southern Italy [see: Italic Dialects].

It came into conflict with Rome during the Punic Wars (264-146 B.C.). In the century after the one in which the Syracusans invented the catapult, Syracuse was home to the great scientist Archimedes.

That early fourth century B.C. type of catapult is probably not the one most of us envision -- a torsion catapult that throws stones to break down enemy walls, but an early version of the Medieval crossbow that shot missiles when the trigger was released. It is also called a belly-bow or gastraphetes. It was attached to a stock on a stand that Ober thinks could be moved a bit for aiming, but the catapult itself was small enough to be held by a person. Likewise, the first torsion catapults were small and probably aimed at people, rather than walls, like the belly-bow. By the end of the fourth century, however, Alexander's successors, the Diadochi, were using the large, wall-breaking stone-tossing, torsion catapults.


Torsion means they were twisted to store energy for the release. Illustrations of the twisted fiber look like twisted skeins of knitting yarn. In "Artillery as a Classicizing Digression," an article showing the lack of technical expertise of ancient historians who describe artillery, Ian Kelso calls this torsion the "motive force" of the wall-wrecking catapult, which he refers to as mural artillery.

Kelso says that although faulty technically, the historians Procopius (6th century A.D.) and Ammianus Marcellinus (fl. mid-fourth century A.D.) give us valuable insight into siege engines and siege warfare because they were in the besieged cities.

In "On Artillery Towers and Catapult Sizes" T. E. Rihll says there are three components for describing catapults:

  1. Power Source:
    • Bow
    • Spring
  2. Missile
    • Sharp
    • Heavy
  3. Design
    • Euthytone
    • Palintone

Bow and spring have been explained -- the bow is the one like the crossbow, the spring involves torsion. Missiles were either sharp, like arrows and javelins or heavy and generally blunt even if not round, like stones and jars. The missile varied depending on the objective. Sometimes a besieging army wished to break down the city walls, but at other times it aimed to burn the structures beyond the walls.

Design, the last of these descriptive categories hasn't yet been mentioned. Euthytone and palintone refer to different arrangements of the springs or arms, but both can be used with torsion catapults. Instead of using bows, torsion catapults were powered by springs made of skeins of hair or sinews. Vitruvius calls a two-armed (palintone) stone-thrower, powered by torsion (spring), a ballista.

In "The Catapult and the Ballista," J. N. Whitehorn describes the parts and operation of the catapult using many clear diagrams. He says the Romans realized rope was not a good material for the twisted skeins; that, generally, the finer the fiber the more resiliency and strength the twisted cord would have. Horse hair was normal, but women's hair was best. In a pinch horse or oxen, neck sinew was employed. Sometimes they used flax.

Siege engines were covered protectively with hiding to prevent enemy fire, which would destroy them. Whitehorn says catapults were also used to create fires. Sometimes they hurled jars of the waterproof Greek fire.

The Catapults of Archimedes

Like the battering ram, animal names were given types of catapults, especially the scorpion, which Archimedes of Syracuse used, and the onager or wild ass. Whitehorn says Archimedes, in the last quarter of the third century B.C., made advances in artillery so that Syracusans could hurl enormous stones at Marcellus' men during the siege of Syracuse, in which Archimedes was killed. Supposedly the catapults could hurl stones weighing 1800 pounds.

"5. This was the siege equipment with which the Romans planned to assault the city's towers. But Archimedes had constructed artillery which could cover a whole variety of ranges, so that while the attacking ships were still at a distance he scored so many hits with his catapults and stone-throwers that he was able to cause them severe damage and harass their approach. Then, as the distance decreased and these weapons began to carry over the enemy's heads, he resorted to smaller and smaller machines, and so demoralized the Romans that their advance was brought to a standstill. In the end Marcellus was reduced in despair to bringing up his ships secretly under cover of darkness. But when they had almost reached the shore, and were therefore too close to be struck by the catapults, Archimedes had devised yet another weapon to repel the marines, who were fighting from the decks. He had had the walls pierced with large numbers of loopholes at the height of a man, which were about a palm's breadth wide at the outer surface of the walls. Behind each of these and inside the walls were stationed archers with rows of so-called 'scorpions', a small catapult which discharged iron darts, and by shooting through these embrasures they put many of the marines out of action. Through these tactics he not only foiled all the enemy's attacks, both those made at long range and any attempt at hand-to-hand fighting, but also caused them heavy losses."

Polybius Book VIII

    Ancient Writers on the Topic of Catapults

    Ammianus Marcellinus

    7 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.

    Ammianus Marcellinus Book XXIII.4

    Caesar's Gallic Wars

    "When he perceived that our men were not inferior, as the place before the camp was naturally convenient and suitable for marshaling an army (since the hill where the camp was pitched, rising gradually from the plain, extended forward in breadth as far as the space which the marshaled army could occupy, and had steep declines of its side in either direction, and gently sloping in front gradually sank to the plain); on either side of that hill he drew a cross trench of about four hundred paces, and at the extremities of that trench built forts, and placed there his military engines, lest, after he had marshaled his army, the enemy, since they were so powerful in point of number, should be able to surround his men in the flank, while fighting. After doing this, and leaving in the camp the two legions which he had last raised, that, if there should be any occasion, they might be brought as a reserve, he formed the other six legions in order of battle before the camp."

    Gallic Wars II.8


    "The tortoise of the battering ram was constructed in the same way. It had, however, a base of thirty cubits square, and a height, excluding the pediment, of thirteen cubits; the height of the pediment from its bed to its top was seven cubits. Issuing up and above the middle of the roof for not less than two cubits was a gable, and on this was reared a small tower four stories high, in which, on the top floor, scorpions and catapults were set up, and on the lower floors a great quantity of water was stored, to put out any fire that might be thrown on the tortoise. Inside of this was set the machinery of the ram, in which was placed a roller, turned on a lathe, and the ram, being set on top of this, produced its great effects when swung to and fro by means of ropes. It was protected, like the tower, with rawhide."

    Vitruvius XIII.6


    "Origin of Greek and Roman Artillery," Leigh Alexander; The Classical Journal, Vol. 41, No. 5 (Feb. 1946), pp. 208-212.

    "The Catapult and the Ballista," by J. N. Whitehorn; Greece & Rome Vol. 15, No. 44 (May 1946), pp. 49-60.

    "Recent Finds of Ancient Artillery," by Dietwulf Baatz; Britannia Vol. 9, (1978), pp. 1-17.

    "Early Artillery Towers: Messenia, Boiotia, Attica, Megarid," by Josiah Ober; American Journal of Archaeology Vol. 91, No. 4 (Oct. 1987), pp. 569-604.

    "The Introduction of Artillery in the Roman World: Hypothesis for a Chronological Definition Based on the Cosa Town Wall," by Valérie Benvenuti; Memoirs of the American Academy in Rome, Vol. 47 (2002), pp. 199-207.

    "Artillery as a Classicizing Digression," by Ian Kelso; Historia: Zeitschrift für Alte Geschichte Bd. 52, H. 1 (2003), pp. 122-125.

    "On Artillery Towers and Catapult Sizes," by T. E. Rihll ; The Annual of the British School at Athens Vol. 101, (2006), pp. 379-383.

    Roman military historian Lindsay Powell reviews and recommends The Catapult: A History, by Tracey Rihll (2007).