My group's siege weapon is the ballista. The ballista was used primarily during the Roman Empire from around 27BC to 476AD. It's essentially a very large cross bow, capable of easily impaling enemies from over 400 metres away. While the Romans were very technologically advanced for their time, they still didn't have access to tools like the ones we have today, this meant that building a ballista back then would have been very difficult. 

Ballistas back in Roman times were made of wood held together with nails as well as rope used to fire the bolts. They had no electric tools and so were limited to hammers, axes, chisels, hand powered drills, saws, files as well as others. Materials for building weaponry and other structures were collected from nearby areas close to where the product is being made or from Rome's various occupied countries. The ability to collect material from countries other than Rome made the process of making and distributing weaponry a lot easier. Mining for gold, copper or silver was a very similar process to what we do today involving fairly large underground mines.   

The fact that the Romans only had access to technology much less advanced than us shows us just how difficult it would have been to build ballistae and other siege weapons. It also shows us how good the Romans were at making these things, especially when there was a high demand for them. The process of making a ballista with power tools and screws alone is complex and requires a lot of skill, further showing us how good the Romans were at this. Studying the Romans and their way of making weapons really makes me feel lucky to have the kinds of tools we have at our disposal, it even makes our ballista feel a little crude, which is surprising considering the advantages we have in our time.