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Index |  History |  Highlights |  WhatWhenWhere
Early civilizations
Greece and Rome
Ingenious devices
     Catapult and ballista
     Greek fire

Middle Ages
The footsoldier
To be completed

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The crossbow: 3rd century BC

A great technological advance in weapons is made in China, in the 3rd century BC, with the invention of the crossbow - a device enabling a bowstring to be tensed well in advance of the shot being made, so that the archer is in effect carrying a loaded weapon. It requires an intricate piece of metal, which the Chinese - with their exceptional skill in the casting of bronze - are well equipped to provide. This is the lock mechanism, restraining the bowstring until it is released by pressure on a trigger.

There are crossbowmen in the Terracotta army of Shi Huangdi. The crossbow in Europe is unknown as a hand weapon until the 10th century AD, though a static version of it is used by the Romans in the form of the ballista.


The catapult and ballista: from the 4th century BC

The principle of the catapult is that of torsion - energy stored in a tightly twisted substance. (An old-fashioned toy aeroplane, with the propeller turned by an elastic band, works on the same principle). In Greek and Roman times the materials to be twisted include natural fibres and the tendons and skins of animals.

One end of a wooden throwing arm is held in these thongs, tightly twisted by soldiers on a winch. The other end of the arm has a basket-shaped hollow in which a heavy stone can be placed. It is winched down to the ground against the pressure of the thongs and is pinned in place. When the pin is removed, the arm snaps upright and the stone is hurled.


By Roman times the catapult has become highly effective - in the damage it can inflict on all but the sturdiest wall, and also as a weapon of terror. Massive stones, lobbed among the defenders of a town, are likely to be extremely unnerving. Modern research, using a reconstruction of the Roman design, suggests that stones of about 50 lbs (20 kg) could be lobbed as far as 400 yards.

Roman soldiers also winch tight the cord of a large wooden bow, mounted on a heavy base. Known as a ballista, this engine is in effect a stationary version of a crossbow. It fires a heavy spear, sometimes flaming to start a fire in the besieged town.


By the 4th century AD Roman legions each have as many as ten catapults and sixty ballistae. The Roman gunners have one essential secret, now lost. For the heavy catapults to remain effective, the elasticity of their cords must be maintained. In modern replicas no way has been discovered of achieving this.

This is perhaps the reason why European armies of the Middle Ages develop a catapult in which a heavy weight replaces the effect of torsion. Suspended from the shorter end of the throwing arm, the weight projects the basket and the ammunition in a rapid arc upwards and forwards as soon as it is released. This form of the catapult, known as the trebuchet, is the last significant siege engine before the arrival of artillery.


Greek fire: 674

In674 a Muslim fleet enters the Bosphorus to attack Constantinople. It is greeted, and greatly deterred, by a new weapon which can be seen as the precursor of the modern flamethrower. It has never been discovered precisely how the Byzantine chemists achieve the jet of flame for their 'Greek fire'. The secret of such a lethal advantage is jealously guarded.

Contemporary accounts imply that the inflammable substance is petroleum-based, floats on water, and is almost impossible to extinguish. It can be lobbed in a canister. But in its most devastating form it is projected, as a stream of liquid fire, from a tube mounted in the prow of a ship. Sprayed among a wooden fleet, its destructive potential is obvious.


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