The siege weapons and tactics collectively referred to as siegecraft, used in the Ancient and Classical eras fall into numerous categories, from the very simple to the complex, depending on the resources of the besieging army and the defensive qualities of the fortification sieged.  For the first few thousand years of human civilization the construction of high walled cities in Bronze Age Mesopotamia, Egypt, Anatolia, and Greece was usually a sufficient deterrent against attack as long as the besieged had food and water and capable defenders manning the battlements.  Siege techniques were elementary at best, with besiegers usually using ladders to overcome moats and walls. However, the primacy of the defensive was challenged during the early Iron Age with the invention of more sophisticated siege technologies and tactics. The first great Iron Age Empire, Assyria, spent a lot of energy in perfecting siege technologies and tactics that were inherited by later Near Eastern civilizations (Chaldeans, Parthians, and Achaemenid and Sassanian Persians).  In the Aegean, the Hellenic Greeks (c.500-338 BCE) were good at creating fortresses, but not as proficient in the art of siegecraft. These shortcomings were addressed by the later Macedonians who, under Philip II (r.359-336 BCE) and Alexander III (“the Great”, 336-323 BCE) and later Hellenistic monarchs, created effective new siege engines to attack fortifications. Many of these new technologies were adopted and perfected by the Romans during that civilization’s Republican (c.509-31 BCE) and Imperial (31 BCE-476 CE) eras.

Because of their size, large siege weapons were constructed on site (sometimes from scratch, other times as reassembled weapons), requiring skilled engineers, a large labor force, and accessible materials including wood, rope, hides, metal fasteners, not to mention the fashioning of wooden, stone and later metal projectiles. The most often used siege technologies and tactics were the simplest to construct and execute (scaling ladders, mobile sheds, battering rams), but all siege equipment were directed at one or more of four objectives: approach the fortification, go over the fortification, go through the fortification, or go under the fortification. In Classical warfare, most successful sieges required prolonged periods of time and huge manpower reserves to move timber and earth, set up cordons, build and man siege engines, and maintain pressure against the enemy’s fortifications, while simultaneously remaining vigilant against relieving enemy forces.

DIRECT ATTACKS AGAINST FORTIFICATIONS

Approaching the Fortification: The Siege Shield and the Mobile Shed

Unfortunately, there is little pictorial evidence of siegecraft dating from the Ancient Period (c.3100-c.1000 BCE).  One of the few examples comes from the beginning of Egypt’s Old Kingdom Period (c.2700-c.2200 BC) with a wall painting at Dehashe depicting soldiers trying to breach a gate by prying it opened with poles. However, this changes in the early Iron Age with the Neo Assyrians (c.850-612 BCE) preoccupation with documenting their city-taking prowess in [bias] relief.  Here, we see etched in stone the use of shield-bearers to provide cover for archers and later larger siege shields to approach a fortification and provide cover for light infantry archers represents one of the oldest siege technologies, one used extensively by the later Greeks and Romans in classical warfare. Larger mobile siege shields on wheels were also developed (called a mantlet in the medieval period). These mobile shields could offer some side protection for two or more attackers and were often employed in front of other mobile siege devices (mobile sheds, battering rams, siege towers) to protect men and animals moving the larger equipment into place against the wall. Over time, these mobile siege shields developed into a full mobile shed, built with a wooden frame and coated with hides and leather. The earliest versions were unwheeled sheds, simply carried to their destination and set down on wooden stakes. Both the Hellenistic Greeks (338-31 BCE) and the Romans (c.509 BCE-476 CE) used these mobile sheds in warfare. Over time, these sheds grew in size and weight and were fitted with wheels and even tile roofs for better protection against projectiles.  The most sophisticated mobile sheds were also equipped with specialized siege devices like battering rams, digging machines and borers.

Top right: Assyrian siege-engine attacking the city wall of Lachish, with infantry archer support. Detail of a wall relief dating back to the reign of Sennacherib r. 700–692 BCE. From Nineveh, Iraq. British Museum. 

Going Over the Wall: Scaling Ladders and Siege Baskets  

The use of ladders as part of a fortification predates the rise of civilization in the Near East.  One of the earliest fortified settlements in human history, Çatal Hüyük (inhabited between c.7500 and c.5700 BCE in south-central Anatolia), did not have exterior doors, instead entry into the multi-building urban complex was by wooden ladder to a rooftop hatch, with the ladder pulled up after reaching the roof.  The first pictorial evidence of scaling ladders dates back to the Egyptian Old Kingdom Period (c.2700-c.2200 BCE).  The construction and placement of scaling ladders took skill as each ladder needed to be built for the specific wall attacked—too short and it did not reach the top of the wall, too long and it could be pushed away be defenders.  Here, simple geometry was used by ancient sources. The Greek historian Polybius (c.200-c.118 BCE) believed that distance between the foot of the ladder and the wall should be half the length of the ladder. Siege engineers understood that if a fortress had several defensive lines with walls of various heights, a stock of ladders of different lengths needed to be constructed.  Sometimes these stocks could be immense.  At the end of the medieval period, the Ottoman Turks constructed 2,000 scaling ladders for their assault on the Byzantine capital Constantinople in 1453 CE.  Besides simple scaling ladders, besiegers also developed folding ladders, rope and leather ladders and nets with hooks (with the latter two often draped over enemy parapets under cover of darkness using a long pole from the ground). Another simple siege device to bring soldiers over a wall was the tolleno, a wooden basket suspended from the end of a long arm attached to a pole on a swivel.  Attackers were lifted in the basket and swung sideways to the top of the battlements, then set down. A celebrated variant of the tolleno were used by the Greeks in their defense of Syracuse in 214 BCE. The famous mathematician and siege engineer Archimedes (c.287-212 BCE) reportedly used this counterweight device mounted on the city walls to hook, lift and drop besieging Roman ships out of the water.

Going Over the Wall: Siege Towers  

The siege tower (belfry) was a specialized siege engine constructed to protect assailants and ladders while approaching the defensive walls of a fortification. The earliest siege towers were employed in ancient Egypt and were used by the early Iron Age Assyrians as well. Both Philip II of Macedon (r.359-336 BCE) and his son Alexander the Great (r.336-323 BCE) made good use of these towers. Alexander famously used them after completing the mole to the Phoenician island fortress during the siege of Tyre (332 BCE). Later Hellenistic rulers built the largest siege towers. Demetrius I of Macedon (r.294-288 BCE) built the Helepolis or “City-taker” while sieging Rhodes, a tower purportedly 130 feet high, sixty-five feet wide and weighing 160 tons. This massive siege tower required 3,400 men working in relays to move it, two hundred turning a large capstan driving the wheels via a belt, and the rest pushing from behind. The casters permitted lateral movement, so the entire apparatus could be steered towards the desired attack point, while always keeping the siege engines inside aimed at the walls, and the protective body of the machine directly between the city walls and the men pushing behind it. The Helepolis was armed with two 180-pound and one 60-pound catapults (classified by the weight of the projectiles they threw) on the first floor, three 60-pound catapults on the second, and two 30-pounders on each of the next five floors. Openings, shielded by mechanically adjustable shutters and lined with skins stuffed with wool and seaweed to render them fireproof, dotted the forward wall of the tower for firing the missile weapons. From their vantage point on the top two floors, attacking soldiers could use two light dart throwers to easily clear the walls of defenders.

At right: Soldiers using siege ladders in Assyrian relief of attack on an enemy town during the reign of Tiglath-Pileser III from his palace at Nimrud.

The Romans built smaller towers (the siege tower used in the Masada siege was just shy of ninety feet high). The siege tower was usually rectangular with four wheels and a height roughly equal to that of the wall or sometimes higher to allow archers to stand on top of the tower and shoot into the fortification. Because the towers were wooden and susceptible to fire, they were often covered with non-flammable covering of iron or water or vinegar-soaked animal skins. Moved into place against the enemy wall, siege towers housed spearmen, swordsmen, or light infantry who shot arrows or bolts at the defenders. When the tower was near the wall, the attackers dropped a gangplank bridging the distance and troops could then rush onto the walls and into the castle or city.  

Going through the Gate or Wall: Battering Rams and Bores

Battering rams are probably as old as fortifications. The first incarnation of this siege weapon was a log with a metal cap carried by a group of men rammed against a door or wall. Both the ancient Egyptians and Assyrians improved on this weapon, removing the log from the arms of men and instead suspending it by ropes or chains in a wooden frame for a pendulum attack.  The Assyrian model was impressive, a six wheeled covered machine, complete with a forward turret above the ram itself manned by archers.  By the seventh century BCE the Assyrians had collapsible battering rams for transport on siege trains. Rams within protected mobile sheds (ram-tortoises) became the norm in the Hellenistic and Roman eras and were widely used in the medieval period.

Ramming attacks were often focused on gates or gate houses, traditionally a weak part of a fortification, necessitating defensive countermeasures like ditches or water filled moats protected by drawbridges, often accompanied by metal-reinforced portcullises. The Hellenistic era (338-31 BCE) also witnessed the invention of small borers (drill bits placed as caps on short logs on rollers operated by two or more windlasses). Borers were housed in armored sheds as well (bore-tortoises) and drilled upward about three feet from the base of the wall (so that debris fell by gravity to the ground) at about one-foot intervals.  Once the cavity was made, dry wood rods saturated with sulfur or pitch were inserted and set alight, compromising the integrity of the wall.  These weapons were particularly effective against brick rather than stone walls and were later used by the Byzantines in their siege attacks.      

At right: An Assyrian battering ram with archer turret attacking an enemy city, c. 865–860 BCE. 

Going Under the Wall: Undermining and Sapping

If going over or through a gate or wall was unsuccessful, besiegers had another, often more difficult option, undermine or sap the fortification.  The tactic of undermining was directed at the above ground base of the wall, while sapping focused on digging an actual tunnel under the wall to either gain entrance to the fortification or to create a cavity that would collapse a portion of the wall.  To undermine a defensive structure required besiegers to physically damage the base of the wall using crowbars, hammers, picks and axes.  This dangerous work required protection from the besieged, and armored sheds (digging-tortoises) were often erected to shield the workers from projectiles and liquid attacks (hot sand, boiled water, pitch or oil). The workers would hollow out a section of the wall about five feet high, as wide as the shed, and to the depth of half the width of the wall. The hollow was reinforced with timber, and once completed, filled with combustible material and set on fire (dry wood and pig carcasses were a favorite because the bodies burned hot). Sapping used many of the same techniques as undermining, but instead of attacking the base of the wall, a wood-reinforced tunnel was dug below the foundation stones.  If the goal were to collapse the wall, the tunnel stopped below the wall’s foundation, filled with combustible material and set on fire.  If the goal was entry, then the tunnel continued into the fortress or city. To stop this from happening, defenders often dug counter-tunnels to block the sappers’ route. The success of these two siege techniques changed where later medieval castles were constructed. 

ATTACKING FORTIFICATIONS FROM A DISTANCE: THROWING WEAPONS

The Hellenic Origins of Throwing Weapons in the Fourth Century BC

Throwing weapons for siege operations date back to Greece in the fourth century BCE with the invention in 399 BCE of the hand-held gastraphetes (or belly bow), essentially an oversized composite crossbow. To increase range and penetrating power, the gastraphetes was made larger and fixed on a shooting platform. This larger siege crossbow was called an oxybeles. However, seeking even more range and penetrating power, Hellenistic engineers replaced the crossbow arm with a torsion powered mechanism based on twisting thick cords of animal sinews or horse/human hair soaked in oil, creating torsion springs fastened to a wooden framework and twisted to a maximum level by special levers, sending large wooden arrows up to 400 yards.  Soon these torsion powered siege machines were adapted for casting stone projectiles, becoming what the Greeks called a lithobolos and the Romans later referred to as a ballista. Later, some of these machines were adapted for indirect fire, becoming what the Romans referred to as catapult scorpions. Siege engineers developed mathematical formulas to determine what diameter of a torsion spring could project an arrow or stone projectile what distance. However, all of these torsion devices had a similar disadvantage, high sensitivity to humidity and the quick degradation of torsion springs.

At right: Photograph of reconstructions of Greco-Roman throwing weapons in the Saalburg Museum in Hessen, Germany.  Left standing: Polybolos, a third century BCE repeating catapult. Right standing: Philo's Chalkotonon, a bronze-spring catapult. Bottom center: Wooden chain-drive mechanism of the Polybolos. Bottom right: Philo's aerotonon, a pneumatic catapult displayed without tripod stand.  Background, on wall: Gastraphetes, a Greek crossbow. 

The Origins of Roman Siege Warfare: The Punic Wars, 264-146 BC

Roman siege techniques were still rather simplistic at the beginning of the Punic wars in 264 BC.  Rome had learned how to organize and sustain long sieges in its wars of Italian expansion during the Early Republic (c.509-264 BCE), while also developing such skills as the escalade (when soldiers attack enemy walls with scaling ladders), battering, and sapping (tunneling under walls).  In fact, it was during this period that the Romans perfected the deployment of the testudo (a formation where legionaries create a protective, interlocking canopy with their shields to protect them from missile fire).  The Romans also became proficient at protecting their siege lines with elaborate field fortifications.  Despite these developments, Roman warfare remained seriously deficient in the use of artillery, specifically catapults, when the First Punic War (264-241 BCE) began.  Roman siegecraft matured during the conflict with Carthage, with Romans eventually mastering the use of artillery, skills learned from contacts with the Hellenistic world, as demonstrated in their multiple year siege and storm of Carthage in the Third Punic War (149-146 BCE).  Our knowledge of Roman siege warfare also increases due to the detailed accounts of Polybius, who was an expert on siege warfare and who gave detailed accounts of the Roman sieges of this period. 

Siege Warfare from Sea: The Sambuca and Floating Siege Tower

The sambuca was a ship-borne siege engine which was invented by the physician and inventor Heraclides of Tarentum (late third to early second centuries BCE) and was first used unsuccessfully by the Romans during the Roman siege of Syracuse in 213 BCE. The sambuca itself was a giant ladder four feet wide and sixty feet long mounted on the front of a double-hulled deck made from two quinqueremes. The ladder was connected by cables to the tops of two masts with pulleys that could raise of lower the ladder as the ship approached the seaward walls of a city. A Sambuca using a different design was used in the first century BC during by Mithridates VI (r.120-63 BCE) of Pontus in his attack on Rhodes in 88 BC and against the coastal city of Cyzicus in 73 BCE.  Additionally, Hellenistic and Roman navies often mounted siege towers on single or double-hulled decks in attempts to gain access to the battlements of seaward walls.

At right: Illustration of a Roman sambuca attached to a double-hulled floating platform. 

Roman Advances to Throwing Weapons: The Manuballista and the Onoger

During the Roman Empire’s Pax Romana (31BCE-180 CE), the Roman army perfected the arrow firing scorpion by introducing an all-metal framework (made of iron or bronze) instead of the metal/bound wooden frames of the earlier model, allowing levers to be placed further apart, increasing the overall power of the machine.  This new manuballista place the torsion springs in metal cylinders, isolating them from contact with moisture. The manuballista fired wooden bolts only fifteen inches in length at extremely high velocities with great accuracy, making it an ideal anti-personnel device as field artillery and mounted on defensive turrets. 

The Romans also utilized torsion powered catapult referred to by the classical sources as an onager (“wild ass”) due to its aggressive kicking action when fired. This machine had one long wooden arm propped up vertically in a sinew bundle.  At the top of the arm was a rope sling.  To operate, the crew pulled the wooden arm back and down to a locked horizontal position, increasing the tension on the arm. Stone projectiles were then placed in the sling. Once fired, the arm quickly returned forty-five degrees to its original position (and slamming against a padded crossbar), with the sling pushing the ball to the top of the point of the arch, increasing the projectile’s velocity.  By the end of the Roman Empire, the onager was the premier stone thrower used by the Roman army. However, with the decline of the Roman Empire, resources to build and maintain these complex machines became very scarce, so the manuballista was supplanted by the simpler and cheaper onager, referred to in the medieval period generically as a mangonel. The Byzantine Empire (337-1453 CE) continued to utilize Roman siege weapons, but in Western Europe, the invasion and settlement of Germanic peoples into the lands of fallen Western Roman Empire led to a decrease in the sophistication of siege technologies and tactics in the Early Middle Ages (c.500-c.1000 CE), with a recommitment to siege weapons and tactics taking place in the High Middle Ages with the introduction of the counterweight trebuchet from the East.

INCENDIARY AND BIOLOGICAL WEAPONS IN SIEGE WARFARE

Early Incendiary Weapons

Incendiary weapons used in siege warfare date to Egyptian Middle Kingdom Period (c.2010-c.1630 BCE), while early Iron Age [bias] reliefs indicate the Assyrians used a variety of incendiary weapons (torches, incendiary arrows and spears) during siege operations. The Hellenic Greek military author, Aeneas Taktikos (mid-fourth century BCE) describes a recipe using resin, sulfur, and tow for incendiary purposes, one that continued to be used into the Roman and medieval eras. During the Second or Great Peloponnesian War (431-404 BCE) the Boeotians created a long rudimentary wheeled flamethrower using this mixture against the Athenians at the siege of Delia, one that pushed air by means of bellows through a long hollowed out log and across a copper cauldron filled with coal, sulfur and resin, thereby feeding the fire. This device successfully caught the wooden fortification on fire.    

At right: Alexander’s siege towers on the mole approaching the Tyrian island fortress. Siege of Tyre, 333-332 BCE. Illustration by Adam Hook. 

Incendiary Missile Weapons

Incendiary arrows are as old as warfare and easy to construct by binding the shaft near the arrowhead with a cloth soaked in oil or resin, setting them on fire. The Romans improved on this design by attaching a small wire box to the arrow shaft filled with an incendiary mixture that, once set on fire by a match, would fly to its target and then spark up again.  The Romans also used a larger manuballista bolt (falarica) with a shaft coated in sulfur, asphalt, and resin bound with tow soaked in oil capable of flying long distances and piercing hide-covered sheds or wooden siege towers or engines, setting them alight. Incendiary arrows and bolts would be an important part of siege warfare in the medieval period as well and were especially effective when fired from large groups of archers or crossbowmen against a target. 

Byzantium’s Secret Weapon: Greek Fire

Although invented slightly beyond the Classical era, perhaps the most famous incendiary weapon of the pre-gunpowder age was Greek Fire, used by the Byzantines in the Early Medieval Period (c.500-c.1000 CE). Invented in the seventh century by Kallinikos, an architect-turned-engineer and refugee from Arab-held Syria, Greek Fire was a perfected recipe of a petroleum mixture first used in the region in the first centuries CE. The Byzantines referred to this substance as “Median oil” (in reference to the region of Medea in northern Iran).  The precise recipe for Greek Fire is unknown, but probably the substance itself was a secret recipe containing naphtha (a flammable liquid hydrocarbon mixture) or a distillation of petrol obtained naturally from the oil-rich Caspian Sea region. This mysterious recipe was heated to increase its flammability and then siphoned through bronze pumps to a nozzle over a match or lantern to ignite it. Once alight, the oil was discharged as a jet stream creating a medieval flamethrower. Greek Fire continued to burn even on the surface of water, making it an ideal naval weapon.  Greek engineers mounted these weapons on a swivel, usually on the bows of ships, so that it could be aimed in an arc and setting enemy ships alight. The Byzantines did manage to keep the recipe for Greek Fire secret for a while, but the Islamic world finally mastered this incendiary weapon in the ninth century, even creating specialized troops called nafatun (“naphtha troops”) to operate the large siphons. The nafatun used this devastating incendiary weapon (whose fire could not be put out with fire, only sand or earth) against crusader armies during the Levantine Crusades (1095-1291 CE).

The art and science of siegecraft mirrors the history of fortification, with besiegers attempting to overcome city and citadel walls using ever developing technologies and tactics.  Methods of attack from the Bronze Age to the beginning of the fourth century BCE were rather similar, however, the invention of siege machinery and projectiles accelerated an arms race across the Near East and Mediterranean basin, resulting in a flurry of military innovation, including new siege machines. This resulted in wholly new or improved designs of mobile siege towers, battering rams, torsion artillery, and new urban military architecture, often with defenders mounting the same machines used to attack the fortification on the battlements or bastions of the defending structure. The increased tempo of this offensive-defensive cycle of innovation would slow in late antiquity and the Early Middle Ages (c.500-c.1000 CE) but would increase again with the construction of new and more sophisticated castles and urban fortifications in the High and Late Middle Ages (c.1000-c.1500 CE), resulting in heavier projectiles and more sophisticated siege engines (trebuchet).  By the late medieval era, new forms of siegecraft were developing, based on new gunpowder technologies, most notably the siege canon, which resulted in a new offensive-defensive cycle between besiegers and besieged.

Bottom right: A Byzantine ship using Greek fire against a ship belonging to the rebel Thomas the Slav in 821 CE. 12th century illustration from the Madrid Skylitzes illuminated manuscript.

Suggested Readings:

Eisenberg, Michael, and Rabei Khamisy, eds. The Art of Siege Warfare and Military Architecture from the Classical World to the Middle Ages. Oxbow Books, 2021.

Kern, Paul Bentley. Ancient Siege Warfare. Indiana University Press, 1999.

Nosov, Konstantin. Ancient and Medieval Siege Weapons: A Fully Illustrated Guide to Siege Weapons and Tactics. Globe Pequot, 2005.