As Arther Ferrill explains in The Origins of War, the offense-defense inventive cycle is a cycle of warfare ingredients in which mobility, security, and firepower are intertwined in such a way that a change in one requires changes in others (44). I mention this only because I understand the development of siege weapons to counteract the efficiency of castle defense as a perfect example of this cycle. This is very apparent in the evolution of offensive weapons that transpired from a simple siege tower to ballista to the advent of gunpowder artillery--all to achieve the same final result: the fall of a besieged castle.
The forerunner of siege weapons was the belfry, and for the most part it was a tower constructed on wheel that could be rolled forward to cover mining operations and Ramming efforts. …
