Technology was also used for designing war and siege engines. We should remember that the Middle Ages were a period of constant small or large scale military conflicts. The knights and the clergy were the pillars of the medieval society. The war and siege engines made military operations and sieges more efficient and effective. Technology was brought into play by medieval armies very early, as can be exemplified by this ballista (from the Greek word meaning "to throw"). This ancient thrower was mostly used during sieges of towns and fortifications.

Its projectiles had a flat trajectory, as opposed to the parabolic trajectory of other types of artillery, such as howitzers or mortars. The considerable strength of ballista's fire resulted from its rigid arms whose ends were fastened with flexible ropes made from horsehair. The first ballistas were probably built in Syria around 500 BC. Roughly at the same time, the Phoenicians invented similar flat trajectory throwers. Initially, the Greeks called them catapults ("katapeltai" in Greek). Later on, in the Roman times, the name scorpion or ballista was coined.