Ancient siege strategies: From towers to tunnels

AMMAN — Bronze Age architecture was characterised by city walls constructed from massive stone blocks. 

To overpower defenders and breach these fortifications, new siege technologies were developed. 

Besieging armies often employed slingers and archers to harass the town’s defenders or even set fire to the walls, supported by chariot-based archers who tracked down those attempting to escape.

However, projectiles alone were insufficient to break into a town during a siege. 

Aaron Burke from the University of California, Los Angeles, identified four primary methods by which a town’s defences could be overcome: escalating, or scaling the walls; breaching the gates or walls; tunnelling beneath the fortifications; or employing deception.

“Historical evidence indicates that successfully entering a town during a siege through these methods almost always guaranteed the victory of the attacking force,” Burke noted. 

“This is because the town’s defenders relied almost entirely on their fortifications, which were the cornerstone of their defence efforts.”

"Success was often achieved by using several of these tactics simultaneously at different points around the town’s walls. This strategy would wear down the defenders and prevent them from concentrating their defences at one vulnerable point. Although siege ladders are not explicitly mentioned, they were likely part of this approach," Burke added.

"One of the most commonly used siege techniques involved the construction of a siege ramp made of earth against the town walls. This allowed troops or a battering ram to be moved up the ramp to strike the walls." 

"While this method was sometimes successful, it could be countered by similar earthworks built by the defenders within the town. 

These internal earthworks were designed to reinforce the section of the wall being battered by the ram, Burke said. 

Another significant technique was the siege tower, referenced in the Mari archives from the Middle Bronze Age in Mesopotamia. According to the Mari texts, these towers were often built on-site, unlike battering rams, which could be transported to the siege site by wagon or boat. 

"Iconographic evidence from the Middle Kingdom Egyptian reliefs at the Tomb of Intef in Egypt also depicts siege towers, indicating their use in warfare against Asiatic towns," Burke said, adding that these towers, constructed from timber, were wheeled up against the town walls.

Siege towers functioned as large, protected ladders, though the design of the fortifications, such as fosse (moats) and sloping ramparts, often prevented their successful use.

Consequently, siege towers likely functioned as freestanding platforms, providing elevated positions for archers to deliver suppressive fire, protecting other operations like sapping, tunnelling, and escalade, he continued, adding when tall enough, the towers allowed archers to fire upon soldiers atop the battlements or within the town.

Regarding breaching, tunnelling, and sapping, reliefs from an Old Kingdom Egyptian tomb of Iny at Deshashe depict an early attempt to break through a town wall.

"Two individuals in the scene use crowbar-like implements to attack a corner of a fortress wall, while a ladder is raised against it behind them," Burke explained.

"This image likely represents one of the most basic methods of wall penetration in antiquity, provided the defenders were distracted. However, classical sources indicate that such attempts often met stiff resistance and frequently failed."

When scaling the walls with ladders was ineffective, and breaking through the wall at ground level was impossible, besiegers resorted to tunnelling under the walls in hopes of causing a collapse. 

"The idea was that the tunnel would undermine the foundation of the wall, leading it to crumble into the cavity created," Burke said.