Most Famous Roman Siege Engines

In the annals of ancient warfare, Roman siege engines stand out as awe-inspiring feats of engineering and ingenuity. These powerful war machines played a pivotal role in shaping the course of numerous sieges throughout the Roman Empire.

From towering ballistae hurling enormous stones to trebuchets launching deadly projectiles, and battering rams crashing against fortifications, these remarkable inventions showcased the Romans’ mastery of military technology.

This article explores some of the most famous and impactful Roman siege engines, providing a glimpse into the strategies that brought down fortified walls and secured conquests in ancient times.


The ballista was one of the most famous Roman siege engines used during ancient warfare.

The ballista was an ancient Roman siege engine that played a crucial role in their military campaigns. It was a powerful and large crossbow-like device used to launch heavy projectiles, such as stones or bolts, over long distances with great force. The ballista was highly effective in breaking down fortifications, causing devastation to enemy troops and structures.

The design of the ballista was similar to a giant crossbow, with two arms made of wood or metal that were connected by a central frame. Tension was applied to the arms using torsion springs made of sinew or hair, which stored energy. When the trigger was released, the arms rapidly snapped forward, propelling the projectile with tremendous force and accuracy.

Ballistae were often used during sieges to breach city walls, towers, and other defensive structures. They could also be employed in open field battles to target enemy formations from a distance. The accuracy and power of the ballista made it a formidable weapon on the ancient battlefield.

Roman engineers and military tacticians continuously improved the design of the ballista, leading to variations such as the larger onager and the smaller scorpio. These siege engines were a testament to the ingenuity and advanced engineering skills of the ancient Romans, and they played a significant role in their conquests and military successes.


A type of catapult that used a torsion system to launch large stones or other projectiles. It was an effective siege weapon and played a crucial role in breaching enemy walls and defenses during ancient Roman warfare. Its power and versatility made it one of the most formidable siege engines of its time.

The onager was a type of ancient Roman siege engine used for hurling projectiles at enemy fortifications during a siege. It was a type of torsion-powered catapult, similar to a large slingshot, and was designed to launch heavy stones, balls, or even incendiary projectiles over walls and into enemy defenses.

The onager operated by using torsion energy stored in twisted ropes or sinew. The weapon featured a large wooden frame with a throwing arm attached to a bundle of twisted ropes or sinew. Soldiers would wind the ropes or sinew tightly, storing potential energy in the process. When released, the throwing arm would rapidly rotate, launching the projectile with great force and accuracy towards the target.


The sambuca, a ship-borne siege engine, was an invention attributed to Heracleides of Tarentum. It was first employed by Marcus Claudius Marcellus during the Roman siege of Syracuse in 213 BC, though its initial use proved unsuccessful.

This ancient Roman siege engine was used for scaling walls and breaching enemy fortifications during a siege. It was a mobile, wheeled platform equipped with a ladder or bridge that could be extended and positioned against walls or ramparts.

The sambuca was designed to allow Roman soldiers to quickly and efficiently assault enemy walls by creating a bridgehead for the attacking forces. It provided a safe and stable platform for soldiers to climb up and over defensive walls, overcoming the vertical obstacles that protected the city or fortress.

The name “sambuca” is believed to be derived from the Latin word “sambucae,” which means “ladder.” The sambuca was one of several innovative siege engines used by the ancient Romans to gain the advantage in their military campaigns and conquests.

While the exact design of the sambuca is not well-documented, it is known to have been an important component of the Roman army’s siege tactics, allowing them to breach heavily defended walls and fortifications and achieve victory in various military campaigns.


The pluteus, also known as a mantlet, was a protective shield used by ancient Roman soldiers during sieges. It was a large, wheeled wooden screen that provided cover to soldiers advancing towards enemy fortifications or walls. The pluteus was designed to protect soldiers from projectiles like arrows, stones, and boiling liquids that defenders might drop from the walls.

When soldiers approached enemy fortifications, they would push the pluteus in front of them to shield themselves from incoming attacks. It allowed them to get close to the walls and use other siege equipment, such as battering rams or siege towers, to breach the defenses.


Scorpio was a smaller and more mobile version of the ballista, often used by Roman legions for both siege and field operations. Image: A modern reconstruction of the scorpio.

The “scorpio” was a type of ancient Roman siege weapon, commonly referred to as a bolt shooter. It was a large and powerful crossbow-like device used for launching heavy bolts or projectiles at the enemy during sieges and battles.

Also known as scorpion, the scorpio was a highly effective weapon, capable of firing large bolts with great force and accuracy over long distances. It was typically mounted on a rotating base, allowing it to be aimed and fired in different directions.

The scorpio featured heavily during the Siege of Amida in 359. Taking place in modern-day Diyarbakir, Turkey, the conflict saw Sasanian Empire lay siege to the Roman frontier city of Amida.

Julius Caesar used the scorpio in 52 BC, during the siege of Avaricum, a conflict that was part of Caesar’s campaign against the Gauls.

Roman engineers and soldiers were skilled in the use of the scorpio, and they deployed these weapons strategically during sieges to weaken enemy defenses and create chaos among the defenders.

Did you know…?

The Scorpio was a versatile Roman siege weapon that came in two main versions. The first version was a horizontal two-armed design, similar to a ballista. It was capable of firing projectiles with great force and accuracy, making it effective for targeting both enemy troops and fortifications.

The second version of the Scorpio was a one-armed, vertical design, also known as an onager. This variant was mainly used for hurling large stones or other heavy projectiles at enemy positions. The onager’s unique design allowed it to create a powerful and sudden release of energy, launching its projectiles with tremendous force.

Battering Ram

A large, heavy log with a metal tip used to break down enemy gates and walls. According to Roman law, defenders who failed to surrender before the first ram touched their wall were deprived of any rights.

The battering ram, known as “aries” in Latin, was a powerful and essential siege engine used by the ancient Romans during their military campaigns. It was a large, heavy wooden beam with a metal head designed to break down enemy walls and fortifications.

Roman soldiers would use the battering ram by repeatedly slamming it against the walls of a besieged city or fortress. The metal head of the ram concentrated the force of the blows, causing structural damage to the walls and weakening their defense.

To protect the soldiers operating the battering ram from enemy projectiles, a moveable shed or roof, called a “tortoise” (testudo), was often constructed to shield them. This allowed the soldiers to continue their assault while being shielded from arrows and other projectiles. It was often the case that the shelter of the battering ram was covered with fireproof material like uncured hides.

Did you know…?

In ancient Rome, during a siege, it was a common practice to use a battering ram to break through the walls of a city or fortress. The defenders of the besieged place were given a chance to surrender before the ram made contact with the wall. If they chose to continue resisting and did not surrender before the ram breached the wall, they would be considered in violation of the customary rules of war, and Roman law dictated that they would be denied any rights or protections. This harsh treatment was meant to discourage prolonged resistance and encourage surrender for the besieged city’s quick capture.

Mines and tunnels

Tunnel warfare, also known as mine warfare, was a common strategy employed by the ancient Romans during sieges. It involved digging tunnels underneath enemy fortifications or walls in order to weaken or breach them from below. This method allowed the Roman soldiers to bypass well-fortified defenses and surprise their opponents from unexpected angles.

The process of tunnel warfare began with skilled Roman engineers digging underground passages towards the enemy’s walls. To maintain secrecy, these tunnels were often dug at night or concealed from view. It was a dangerous task as the Romans had to avoid detection by the defenders, counter enemy mining attempts, and handle the risk of tunnel collapses.

Once the tunnel reached its target, Roman soldiers would place large quantities of combustible materials, such as wood, straw, and pitch, at strategic points within the tunnel. When the time was right, the materials were set alight, causing the tunnel to collapse and weaken the enemy’s fortifications above. The resulting breach in the walls would allow Roman forces to storm the city or fortress.

Tunnel warfare required precision, patience, and engineering expertise. The Romans excelled in this strategy, often gaining a significant advantage in battles and sieges. However, it was a risky endeavor, and failure could be costly in terms of lives and resources.

In ancient Rome, it was not uncommon for tunnels and trenches to be deployed for guerrilla-like warfare, usually against the Roman Empire. For example, Roman forces had a tough time dealing with the tunnels dug up Jewish rebels in Judea during the Bar Kokhba revolt (132 – 136 AD).The Romans countered the tunnels by burning materials in the tunnels in order to smoke out the rebels or suffocated them to death.

Also, the defenders of the besieged city could counter mines using smoke to force the sappers out of the tunnel.

During the Bar Kokhba revolt (132 – 136 AD), Roman forces faced a formidable challenge in dealing with the intricate tunnels dug by Jewish rebels in Judea. To counter this underground threat, the Romans employed a strategy of burning materials within the tunnels to smoke out the rebels or suffocate them to death. These defensive measures were aimed at disrupting the rebel activity and undermining their advantage in the subterranean warfare.

Siege Tower

A mobile wooden tower that allowed Roman soldiers to scale the walls of fortified cities during a siege.

The siege tower, known as “turris” in Latin, was a remarkable and vital siege engine used by the ancient Romans during their military campaigns. It was a large, mobile, and heavily fortified tower-like structure designed to provide an advantage in assaulting enemy fortifications.

Constructed with multiple levels and platforms, the siege tower allowed Roman soldiers to climb to elevated positions and attack fortified walls at close range. It was equipped with a drawbridge at the base, enabling troops to rush out onto the walls or battlements of the besieged city or fortress.

The siege tower played a critical role in overcoming the defenders’ advantage of height and was instrumental in breaching enemy walls during sieges. It provided Roman armies with an effective means to gain access to well-fortified cities, making it an essential and formidable tool in their military campaigns.

Julius Caesar was deeply fascinated by the integration of advanced siege engines, strategically organizing their deployment to maximize battlefield efficiency. The Roman dictator is said to have used a ten-story siege tower during the siege at Uxellodnum in Gaul.

At Jotapata, during the Jewish rebellion, the Roman siege towers reached a height of 50 feet. They were also plated with iron to keep them safe from fire hurled at them by the enemy. At Masada in 72/73 AD, some the Roman siege towers reached 75 feet high. Similar siege towers were used by the Romans at the Battle of Jerusalem in 70 AD. At that battle, the defenders managed to bring down some of the siege towers by tunneling underneath them and then causing them to collapse.


When translated to Latin, Corvus invokes the meaning of “crow” or “raven”. The corvus was a boarding device used by the ancient Romans during naval battles. It was essentially a large boarding bridge with a spike at the end.

When the Romans approached an enemy ship, they would drop the corvus onto the enemy deck, piercing it and allowing Roman soldiers to quickly board the enemy vessel. This gave the Romans an advantage in close-quarters combat and allowed them to engage in hand-to-hand combat, where their superior infantry skills could be put to use.

This siege engine played a crucial role in several Roman naval victories during the First Punic War (264 – 241 BC). According to 2nd century BC Greek historian Polybius, Corvus were fixed in the planks of the decks of the ship. The dimension of this naval boarding devise was usually 36 ft long and 4 ft wide.

Bear in mind that at the time of the First Punic War, Rome did not have the same naval strength as Carthage. Therefore, the Corvus allowed the Romans make good use of their infantry power at sea. For example, the corvus and other naval innovations proved extremely advantageous at battle such as Eknomos in 256 BC, Battle of Tyndaris in 257 BC, and the Battle of Mylae in 260 BC.

Perhaps the only serious disadvantage of the corvus was the fact that it could not be deployed in rough seas. This flaw has been attributed to as one of the reasons why Rome gradually abandoned the corvus after the First Punic War. The boarding device would be replaced with more innovated devices like the harpoon.

The corvus was a notable Roman naval boarding device used during the First Punic War to secure naval victories.


The Testudo, also known as the “tortoise formation,” was a defensive tactic used by Roman infantry during sieges or in open battle to protect themselves from missiles, particularly arrows and javelins. The formation involved soldiers standing close together in a tightly packed formation, holding their shields above their heads and on the sides, creating a shield wall that provided almost complete coverage from above and the front.

The shields were held close together, forming an impenetrable barrier against incoming projectiles, hence resembling a tortoise shell, hence the name “Testudo” (Latin for “tortoise”). Soldiers at the front and sides of the formation would also hold their shields forward to protect the soldiers in the center.

The Testudo was an effective defensive strategy against missile attacks and allowed Roman soldiers to advance more safely towards enemy fortifications during sieges or to hold a strong defensive position on the battlefield. It was a versatile formation that played a significant role in the success of Roman military tactics.

Frequently asked questions

These siege engines played a crucial role in Roman military campaigns and were instrumental in capturing enemy cities and fortifications. They were a testament to the engineering prowess of the ancient Romans and their strategic approach to warfare.

Here is what you need to know:

How effective was the scorpio?

The Scorpio was a deadly Roman siege weapon known for its armor-piercing abilities. It was aptly named after the scorpion due to its deadly sting. Unlike larger siege engines like battering rams, Scorpios were designed to target enemy troops rather than break down fortifications. They were lightweight and compact, making them easily operable by just one or two men. This portability allowed them to be mounted on or within siege towers, providing a mobile and versatile solution for taking down enemy soldiers during sieges. The Scorpio’s accuracy and power made it a formidable tool on the battlefield and a valuable asset in ancient warfare.

How effective were the Roman Ballistae?

Roman 'catapult-nest' on Trajan's Column

A large crossbow-like weapon used for shooting heavy bolts or stones at enemy fortifications and troops.

The ballista was an advanced and highly valued weapon that underwent further development under the Roman Empire. It became a crucial component in the Roman army’s artillery, known for its effectiveness and versatility in various military campaigns.

During the late Roman Republic, the ballista was prominently used by Julius Caesar in his conquest of Gaul (modern-day France) and during his two expeditions to Britain (in 55 and 54 BC). For example, the Ballistae featured during Rome’s siege of Alesia in 52 BC. Caesar recognized the weapon’s potential in siege warfare and battlefield engagements, and he strategically employed ballistae to great effect in his military campaigns.

The ballista’s design and construction allowed it to launch large bolts or stones with incredible force and accuracy, making it a formidable weapon against enemy troops and fortifications. Its ability to deliver devastating blows from a distance gave the Roman legions a significant advantage on the battlefield.

As the Roman Empire expanded, the ballista remained an essential tool in the military’s arsenal, utilized in various conquests and defensive operations. Its continued development and usage showcased the Romans’ prowess in engineering and military tactics, contributing to their dominance in ancient warfare.

How did the Onager operate?

The onagers used by the Roman Empire were powerful siege weapons primarily employed for the purpose of besieging enemy forts or settlements. They were capable of launching large stones or rocks over significant distances with great force. During a siege, the stones could be combined with a flammable substance, such as pitch or oil, and then set on fire before being hurled at the enemy’s fortifications.

The combination of the heavy impact from the large projectiles and the potential for causing fires made the onagers a formidable weapon on the battlefield. They could cause significant damage to fortifications, walls, and structures, making it easier for the attacking forces to breach enemy defenses and gain entry to the besieged areas.

By utilizing onagers, the Roman forces could weaken and disrupt enemy defenses, creating openings for infantry assaults and leading to successful conquests during military campaigns.

How did a Roman battering ram operate?

The battering ram was a crucial siege weapon that allowed Roman armies to breach enemy fortifications, creating openings for the attacking forces to storm into the city and engage in close combat. It was a symbol of Roman engineering and military prowess and played a significant role in their success during sieges.

During the siege of Jotapata, the Romans used a powerful battering ram. According to Jewish historian Flavius Josephus (37 – c. 100 AD), the battering ram was a powerful siege weapon used in ancient warfare to break through the fortified walls of cities or castles.

It resembled a large wooden beam, similar to a ship’s mast, with one end covered in iron shaped like a ram’s head, which gave it its name. The ram was suspended from a balance arm, supported by posts fixed in the ground at both ends.

To operate the battering ram, a significant number of men would pull it back using cables, and then push it forward in unison with great force, causing the iron head to strike against the wall of the besieged city or fortress. This repeated action would eventually weaken and breach the wall, allowing the attacking forces to enter the city and conquer it.

The Roman battering ram was not only powerful, but it was also an effective siege weapon. Josephus states that no defensive tower or wall, no matter how strong or thick, could withstand the relentless and forceful blows delivered by the battering ram.

The weapon’s impact was so powerful that even well-fortified structures often couldn’t withstand the first strike, let alone endure repeated blows. The battering ram’s ability to break through formidable defenses made it a fearsome tool in ancient warfare, enabling attacking forces to breach enemy fortifications and achieve victory in sieges.

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