The ballista was an ancient equivalent of a mounted machine gun: it was stationary, accurate, fast, and deadly. very VERY deadly. It was created in ancient Rome but first became common under the rule of Alexander of Macedon and again later by Julius Caesar. The ballista was basically a large mounted crossbow (crossbows hadn’t been invented).
Before the ballista, the bow was the main long ranged weapon which is why the ballista is very similar to one. The ballista has many advantages over the bow such as its range. Unlike the bow which was all one piece, the ballista has two separate arms powered by twisted rope torsion coils. These coils gave the ballista much more power and therefore range than a bow. This increase in power also enabled much larger projectiles. It fired bolts (spear-like arrows), either shorter dart like bolts for accuracy or larger spear like bolts (several feet in length and several inches in diameter) for destruction. The tips of the bolts were often dipped in a flammable substance and lit just before firing for a devastating napalm effect. This large ammunition allowed the ballista to cause much greater damage with accuracy than any long-range weapon before it.
The ballista had an incredible range for the time period. It was able to kill soldiers up to 500 yards away, that’s five football fields away. It was also very accurate, ballista operators were recorded picking off individual soldiers one to two hundred yards away. At greater lengths though, it was more effective against groups of soldiers such as a charging army. a pair of ballista operators could fire three to four bolts a minute enabling them to fire repeatedly on an approaching army. there would dozens of ballista placed at the edge of the battle field firing over their allies into the oncoming enemy. With the Ballistae(plural of ballistae) and bowmen firing simultaneously, the Romans would create a cloud of arrows large enough to block out the sun, bringing an abrupt stop to their enemy’s charge.