Breaking Walls: Siege Weapons from the Ram to the Field Gun

The oldest answer was brute force: a heavy beam, often iron or bronze tipped, driven against a gate or wall. Assyrian reliefs from the ninth century BC already show wheeled, armored rams, and later versions sat inside a hide-covered shed to resist fire from above.

Where the ram broke a wall at its base, the siege tower removed the wall's height advantage. Wheeled, multi-story and built to let troops cross at the top, it was answered by fire aimed at its wooden frame, as at the Hellenistic Helepolis used at Rhodes in 305 BC.

The ballista brought engineered range to the siege. Two skeins of twisted sinew or hair rope powered flat-trajectory bolts or stones, and Roman legions fielded smaller mobile versions called scorpiones.

The single-armed onager threw stones in a high arc, suited to attacking fortified positions rather than troops. Ammianus Marcellinus describes its operation in the fourth century AD, and its high-arc principle pointed toward the later trebuchet.

Greek fire moved the siege to the water. Credited to Kallinikos of Heliopolis in the seventh century and sprayed from pressurized bronze tubes on Byzantine ships, it burned on water and is credited with helping repel Arab sieges of Constantinople in 674 to 678 and 717 to 718.

Naft shows the same petroleum chemistry used on the other side of the frontier. Specialist troops called naffatun, in fireproof suits, threw copper vessels of burning naphtha, and Ayyubid and Mamluk armies used it heavily against the Crusader states.

The counterweight trebuchet replaced muscle power with a falling weight. The earlier traction form reached the Byzantines, Persians and Arabs by the sixth to seventh centuries, while the counterweight form is first illustrated in a commentary on Saladin's conquests written in 1187.

Gunpowder first arrived as a small weapon, a metal tube on a pole fired with a lit match or hot iron. It emerged in China by the thirteenth century and spread across Eurasia in the fourteenth, heavy and slow but armor piercing and easier to train for than archery.

The culverin carried gunpowder into the long-range artillery role. This fifteenth century long-barreled cannon had a flat trajectory and long reach, and culverins and their smaller relatives formed a substantial part of the English fleet armament against the Spanish Armada in 1588.

The path ends with standardization. Adopted by France in 1765, the Canon de 12 Gribeauval weighed roughly half as much as the older Valliere guns without losing range, with standard calibers, interchangeable parts, a calibrated gunsight and an elevating screw, and it stayed the mainstay of French field artillery through the Napoleonic Wars.