The Catapult

Catapults

The predecessor of all artillery was the bow and arrow. From there the idea of throwing things spread and was developed. Bows continued to be popular since they could be carried and wielded by a single soldier, but there was also development in larger bows that could throw larger projectiles farther. These larger bows were called ballistae: "Early Greek ballistae are best described simply as oversized crossbows, although in point of historical fact technological development seems to have proceeded the other way around and derived the smaller weapon from the larger engine."[Van Creveld 32] These engines were reasonable accurate with a range between 200 and 300 meters, but they could not be fired very quickly. The fundamental difference between the ballista and the bow from which it was derived was its ability to store power: a bow could be drawn back, but one the archer took his hand off the string all the power would be released. The ballista could be cocked, and the power would remain while the operators turned their attention to other details, such as aiming and waiting for the perfect moment.[Van Creveld 32]

Figure 1. From Dawson

Ballistae were made from a combination of materials, which eventually proved to be their weakness. "...artificers may have started by analyzing the contribution made to the total power of the composite bow by each of the three resilient materials employed in it, namely sinew, wood and horn. ...they may have reached the conclusion that the sinew provided the most power, and that, to some extent, the wood and horn were hindering the development of greater force."[Marsden 17] This was circumvented by using ropes, usually sinew ropes, twisted into skeins to act as springs and store power. Sinew ropes were thought to be best, but other materials such as hair was occasionally used. "Vitruvius does not distinguish between the merits of hair and sinew, though he indicates that, of the former material, women's hair is best...Vegetius strongly emphasises the importance of sinew for atrillery; to him hair from the manes and tails of horses is merely a useful substitute, and women's hair is excellent in an emergency."[Marsden 87-8]

Because these engines were large, moving them was difficult. Some of them could be dismantled and carried in pieces on the back of pack animals, but most were simply built in place. This required having specialists available, as well as tools and materials to build with. "Devices too heavy to be easily moved about were not, of course, useful for field warfare. On the other hand, one suspects that it was precisely for this reason that nomadic people such as the Mongols who carried all before them in the open field ran into difficulties when they entered western medieval Europe..."[Van Creveld 31]


Range of Catapults

At this point, it is neccesary to point out that "catapults" can be divided into two groups, those that shoot arrows and those that throw stones. Of the former, the ballista is the notible example and provided, like the bow, a shot that was most effective when fired at a low angle. If it were fired at a higher angle, it would travel farther but it would also trade a lot of its horizontal speed (what makes it dangerous since its sharp point was in the front) for vertical speed and height. The stone throwers, such as the onager, had a larger effective range since the projectiles were much heavier and thus could cause damage no matter how it landed.[Marsden 90] It was from this line that the trebuchet came.

Here is a table from Marsden 86 that has ranges of modern reconstructions of various catapult designs.

Two-cubit arrow-shooting catapult370 metres
Three span arrow-shooting catapult (based on the remains found at Ampurias) 305 metres
Small stone-thrower (with a 1.5-mina stone)184 metres
Small stone-thrower (with a 1-lb. lead shot)over 300 metres
Smaller onagerover 200 metres
Larger onagerover 300 metres

Use of Catapults

Since walls were one of the most insurmountable forms of defense a city could create, it would seem logical that it was against that that catapults were most commonly directed. Catapults have also been used directly against troops, as well as being mounted on ships.

Catapults such as the ballista were intended for use directly against troops, as very large bows that could pierce a shield and still have enough energy to do damage to the sheild's holder. At the siege of Jerusalem in A.D. 70, stone throwers were used: "'and their impact was not only irresistible to the front rank, but also to the men behind, to a considerable distance'. At 400 yards, the one-talent shot ploughed its way through several ranks."[Marsden 95] These catapults were land-based, but catapults have found use on ships. During an attack on a Rhodian harbor, " [Demetrius] put on board his ships, preparatory to attacking the Rhodian harbour, 'those of his three-span arrow-firers that shot the furthest' ([greek translation ommitted]). When actually inside the harbour, he hindered the Rhodians, who were trying to improve their fortifications in that area, by firing at them with 'the lesser arrow-firer capable of long range' ([greek translation ommitted])."[Marsden 89]

Catapults reached their peak of development around 200 B.C., when they were understood well enough to have mathematical formulas that predicted their power based on their size; after that, development ceased during the early middle ages like so many things. It was rediscovered by 1050 and was enjoying much popularity. [Van Creveld 32-2] As with many technologies, there were those who objected (on grounds other than they didn't have them): "In Western civilization until about 1500 A.D., the most important reason why some weapons were considered unfair was because they enabled their users to kill from a distance and from behind cover. The victim being unable to retaliate, such weapons obscured the vital distinction between war and plain murder... [An example was] the catapult, which was perceived as a device that would render valor superfluous in war." [Van Creveld 71]


Figure 2. Probably an onager. From Dawson

From Catapult Museum Online

Late in the third century CE, Roman artillery craftsmen devised a solution to one of their biggest problems. This problem was the stone throwing Palintones catapult, the biggest of all catapults, called a ballista by the Romans. The largest of these engines were capable of throwing 100 lbs stones more than three hundred yards. These engines were extremely complicated to built and because of their size were also difficult to transport. To remedy this problem the Romans created the onager, the engine most people today associate with the word catapult.

Named after a pig that kicks rocks behind itself when chased the onager was much easier to construct and maintain than the palintonos because it was basically half the machine. The frame of the onager was composed of thick rectangular pieces of wood aid flat on the ground. Through each side of the frame were bored two holes through which ran the skeins of rope The ropes were held in place by a washer and counterplate. In the middle of the sinew ropes stuck a single arm that ended in a cup or a sling fitted for a stone. The arm was cranked down with a lever, further torsioning the skein, and was held in place by a ratchet and pawl. When released the arm would snap forward into a supported upright which halted the arm and drove the shot towards its intended target.

From Rowlett Volume M

mina - a historic unit of weight, originating in Babylonia and used throughout the eastern Mediterranean. The mina is roughly comparable to the pound, but over the centuries it varied quite a bit. In Babylonian times it was a large unit, roughly 2 pounds, almost as much as a kilogram. The Hebrew mina, frequently mentioned in the Bible, is estimated at 499 grams (1.10 pounds). The Greek mina was equal to 431 grams (0.95 pound). In Biblical times the mina was equal to 60 shekels, and there were 50 minas in a talent.


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Written by Andrew Vick