The development of torsion artillery engines that were powerful had a signifact impact on siege techniques and provided  an impelling force for an alteration in the design in fortifications around the Mediterranean.  Catapults became an important component of warfare during the fourth century.  Those with the knowledge of catapult construction and maintenance were offered particular benefits such as removal from the rank and file,  steady, rewarding work and the ability to survive political purges.

There are three major types of catapults, and they are:

• The ballista
• The mangonel
• The trebuchet