The Chinese and Greeks invented crossbows more or less simultaneously, around the 7th - 4th century BCE.
The Greeks developed them into field artillery weapons like the gastraphetes and later siege catapults like oxybeles and lithobolos, but never used light, hand-held crossbows.
The Chinese did.
They even developed a repeating crossbow that had limited range and power, yet reloaded very quickly.
The crossbow made a comeback in Europe in the Middle Ages.
It was the most popular missile weapon in Europe from 1200 CE to 1460 CE.
The most famous Medieval crossbowmen came from the Italian city of Genoa and from Iberia.
The crossbow was phased out in the decades around 1500 CE, when gunpowder firearms took over,
but remained popular as a hunting weapon for centuries more, because it is silent.
Crossbows use shorter and thicker arrows than handbows, called bolts.
Bolts with flanged tips are called quarrels, but this name is sometimes used for all kinds of bolts.
Some crossbows do not shoot bolts but stones or bullets and are called 'stonebows', 'arbusts' or 'bullet crossbows'.
The latter are used exclusively for hunting small game.
Crossbows evolved from light to very powerful weapons.
During this evolution, ever more ingenious devices were developed to help the crossbowman pull the string up to full tension strength.
Many of these heavy weapons were operated in teams of two men, one wielding the crossbow and another protecting both
with a very large "pavise" shield and sometimes a spear.
Several types of crossbow can be discerned:
- The primitive crossbow. This weapon is tensed with both hands and arms. More advanced models have a stirrup at the fore-end of the stock, so the wielder can use the strength of one leg too.
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The composite crossbow was introduced in Europe in the late 12th century CE.
This type is made of wood and horn, just like a composite handbow.
It has greater tensile strength and requires the help of a tension-tool to to tense fully:
- cord and pulley: increases strength by a factor of 2, in use until 1320 CE
- claw and belt: uses leg-power instead of arm-power, like with stirrup
- goat's foot lever: leverages arm strength by a factor of about 4 to 5, can be used by cavalry, in use 1350 - 1500 CE
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The steel crossbow was introduced in the late 14th century CE.
This heavy crossbow requires heavy tools to bring it up to full tension strength:
- screw and handle: clumsy and tedious, but powerful
- cranequin: successor to screw and handle, can be used by cavalry, introduced 1480 CE
- windlass: powerful and faster than a cranequin, but heavier
Crossbows largely replaced handbows though not entirely. They have more power, but a lower rate of fire. This makes them effective against at heavily armored targets, but unsuitable for mass volleys. The greatest advantage of the crossbow over the handbow is that it is easier to handle, requiring less strength and skill.