Crossbow
The Greeks invented crossbow separately in 4th century B.C. The Romans called the weapon arcuballista. Crossbow was a very popular weapon in the Middle Ages as it was strong and accurate and could be used as a sharpshooter weapon. The Arabs call crossbow qaws Ferengi, "Frankish bow", as the Crusaders used crossbow a lot. A good crossbow can shoot the bolt with such immense power that it may pierce armour. Against unarmoured light opponents, even a single bolt may be lethal.