History of the crossbow

China

The history of the crossbow dates back to 4 th century BC in Ancient China. Early finds of crossbows were discovered tomb at Saobatang, Huan dated to 4th centuru BC. Repeating crossbows were discovered in tomb at Quinjiazui, Hubei dated to 4th century BC. Repeating crossbow is first mentioned in the Record of Three Kingdoms.
The crossbow is is the most frequently weapon mentioned in the ancient chinese sources. It was wiedly used by army of Hun dinasty (202 BC-220 AD). Crossbow was often given credit for the Han army`s superiority over its enemy.

Chine also invented muliple-bolt crossbow. Lian Nu was generic term for any type of crossbow which fired multiple bolts at the same time. This was huge crossbow that was mainly mounted on wheels.

Chu-ko-nu was popular hand held repeating crossbow in China. Invented by Chu Ko Liang during later Han period. It was for high "rate of" against massed troops at ranges not exceeding 50-75 yards.

Chinese repeating crossbow:

Greece

In Grece in 399 BC was invented a mechanical arrow firing catapult called katapeltikon. This weapon was later used in battles. In 3rd century BC engineer Ctesibius invented hand held crossbow gastraphetes (belly shooter). Gastraphetes was using composite bow and was cocked by resting the stomach in a concavity on the rear of the stock and presing down. It was a big weapon.

Gastraphetes:

Roman empire

Romans was using huge siege machine that was made by the same principle as a crossbow. In Roman times crossbow was named arcubalista. Romans was using ordinary small hand held crossbows arcubalista. Vegetius (4th century) write about it in his treties on military art. Manuballista hand held crossbow was also used by Romans.

Roman arcubalista:
 

Manuballista: