Editing Siege Weapon (section)

===Ballista===
One day a Greek man looked down at his [[crossbow]] and thought "what if I made it bigger?". They came with two designs: a ridiculously large ''Oxybeles'' (which was essentially a larger version of the gastraphetes crossbow with wooden prods), later known as a ''scorpion'' (which was commonly used as anti-siege-weapon weapon mounted on fortifications) and an "even bigger mounted crossbow" called the ''ballista'' (which used coiled rope for torsion rather than wooden prods). Adding a windlass turned chain and a hopper magazine resulted in the ''Polybolos.'' Contrary to popular belief ballista is not an oversized crossbow - as the tensions, stresses, and material resistances scale differently and cause huge wooden bows to break and huge metal bows to deform from straining under such pressure. Thus Greeks devised a system that uses twisted ropes in which bow arms are fixed to store energy to the point it can hurl spear-sized bolts with enough power to break gates and warship hulls. In Roman times, the ballista was said to be terrifyingly effective in terms of both accuracy (to the point of picking off individual soldiers) and power (with tales of it piercing armored warriors and leaving them impaled to a tree).

* '''Polybolos''': roughly meaning “multi-bolt thrower” in Greek and also known as a "repeating ballista," the Polybolos more often resembles a big crossbow than a ballista since the arms are fixed to the "stock" and don't twist around to fire it; though some versions do use arms wedged into tense bundles of twisted ropes like regular ballista. The repeating ballista was fired by turning a wheel connected to a chain drive forward to cock it, then turning it the other way to load it again from a hopper on top of the stock and fire it. Turning the wheel at the back of the crossbow counterclockwise pushed a sliding plank called the mensa (like that from the Gastrophetes/Oxyboles) forward.  Once driven forward sufficiently, the latch claws at the back of the plank are pushed up by a lug under the plank and hold the drawstring in place. Then, turning the wheel clockwise drew the drawstring back as the plank slides backwards. At the same time, the motion of the plank drives a screw threaded pole (in contact with the plank by a block with a sliding nut) to rotate and load a bolt (via a built-in notch on the rod) onto the body of the plank from the hopper on top. Pulling the wheel back to the very end will bump the latch on another lug that triggers the latch into releasing the drawstring and firing the bolt.

*  '''Springald''': Also known as the "skein-bow," it was the transitional successor to the Ballista before the arrival of cannons, the Springald began replacing it in the 11-12th century. While it used coiled rope and torsional power to fire bolts, rocks, and even containers of Greek Fire, it physically differed visually by looking like a cubical scaffold with the arms swinging inward rather than outwards like the ballista. 

Serving as highly accurate artillery (multiple stories exist of single soldiers getting sniped by bolts), Ballista was used by both the Greeks and Romans and later through Medieval times, for a long time coexisting with early gunpowder artillery until development of cannon technology  made it obsolete. Not only were cannon barrels relatively simple to cast and maintain, but they were not as finicky or vulnerable to humidity or weather compared to wood and rope.