The Siege

Welcome to my guide on how to write a siege. In previous posts we’ve looked at fortifications of the Middle Ages—castles, keeps, towers, gates, and walls (click here for Part One and here for Part Two). Today we’re going to look at how to bring them down.

Some of the most iconic scenes in fantasy involve sieges—Helms Deep, Dros Delnoch, Minas Tirith. A lot goes into a siege logistically and tactically, meaning it’s crucial to have a good understanding of techniques to get by defensive structures.


The development of fortifications and the development of siege tactics are inextricably linked. It seems to be human nature that if someone builds a wall, someone else wants to tear it down. The best way to explore tactics is to work our way through a siege from the perspective of the attackers.



The first obstacle any attacker would have to overcome is the moat (if there is one). If the moat was small and shallow it could either be jumped across or planks placed over it to make walkways. Any bigger it had to be filled in. If it was a water-filled moat, that water first had to be drained out, and one way of doing so was by digging drainage holes and then connecting them to the moat. Rocks, dirt, wood, or whatever else the attackers could get a hold of, were used to fill in the moat. Not only did they have to do all this manual labour, but they had a load of archers raining hellfire at them.



Good luck filling that moat in


The Battering Ram

Moat dealt with, next came the gate and walls. One of the oldest but most efficient methods of getting through a gate was a battering ram, which consisted of a heavy log or tree trunk. A battering ram carried by men alone was sufficient to get through small gates, but larger gates required something a bit more robust.


Enter the cat, a carriage in which a battering ram was hung and then swung at the gate. It was also known as the mouse, weasel, and sow. To increase the strength of the ram it was banded with iron rings and reinforced with an iron head to stop it from shattering. The carriage had a roof covered with wet hides to protect the ram operators from projectiles and fire. Instead of a ram, some cats had an iron pole attachment which was used to chisel away at the mortar of the walls. Cats were also used without a ram to provide a safe space for siege engineers to go about undermining the walls or filling in moats.

battering ram on wheels

To counter these cats, the defenders used a few cunning tactics. The easiest one was to smash them to bits with heavy rocks. Another tactic adopted by the Muslims in the Levant and adopted later by the Crusaders was to try and hook the ram and flip it over. Apparently, it was pretty effective.

medieval cat joke.jpg

Another type of medieval cat. This picture tickled me.


The Good Old Ladder

The quickest, most direct and straightforward approach to overcoming the walls and gate was the escalade: scaling the walls with the help of a ladder. It was a tad dangerous, though, suicidal in some cases, with no protection other than the armour on their backs and the cover of friendly archers. When the height of walls was raised later in the Middle Ages this approach became redundant.



Siege Towers

And so siege tower came about, also known as the belfry. This siege engine has ancient roots beyond the Middle Ages but featured heavily during The Age of Castles. It consisted of a wooden tower built on wheels. Inside were several levels which the attackers could ascend.


The top-level usually consisted of a drawbridge which could be lowered onto the battlements and from there the attackers poured forth. Some had a level above this which provided a platform for attacking archers to shoot at those upon the battlements. And some towers even had a battering ram on the bottom level. The above image shows all three.

The siege tower did have weaknesses. Being wooden it was susceptible to fire, which is why they were usually covered in wet hides. One type of fluid used to wet the hides was urine. So before battle piss was splashed about, leaving a nice stench to emanate across the battlefield. Lovely. The transportation of siege towers was also tricky. Given their shape they were prone to toppling when on uneven ground, which was tricky when faced with moats or inclines. 

It was imperative to the success of a siege to pin down the defenders with archery and missile fire which allowed the siege equipment to advance. Attackers set up contraptions called mantlets, which were wooden shields held upright by beams, around 2m by 2m, to allow archers to provide cover.





One of the main tactics adopted to bring down a wall, and perhaps the most dangerous, was mining. Under the protection of cats and hefty shields, miners used picks and other tools to destabilise walls.

Moats made mining difficult. One of sufficient depth could dissuade even the most ambitious of miners, but shallower moats could be dug under. Reaching the foundations of the wall, the miners filled the tunnel with flammable objects and set it afire. The tunnel supports collapsed in the heat, bringing down the tunnel and the ground above. So too went the base of the wall.

The defenders had methods for detecting when a mine was being dug. They used the Jurassic Park method of watching a bowl of water for ripples. To defend against mines they dug counter-mines to collapse those of the attackers, smoked them out, or sent down troops to kill the diggers, ending the threat by collapsing the mine.



There were a number of projectile hurling siege weapons used in the Middle Ages, each with its strengths and limitations.

catapult, treb, ballista.jpg

Crafted in the Roman era, the ballista was a giant crossbow. A single bolt could cleave through groups of men, though it wasn’t much use against stone walls.

There was the catapult too, also known as the mangonel, which consisted of a wooden beam with a bowl at one end. The beam was winched down and released to spring the contents of the bowl forwards. Projectiles from catapults had a low velocity and usually weren’t heavy enough to cause significant damage. It had a range of about 500 meters, beyond the reach of archers. Catapults were used in groups, or batteries, to target sections of wall or defensive positions. Using them in such clusters caused massive damage.

The trebuchet was similar to the catapult but instead of a bowl it had a sling in which projectiles could be loaded and hurled. It was better able to throw heavier missiles than the catapult—as heavy as 150 kilograms, which is about the weight of a panda. Yes, a panda. It operated much like the modern day mortar, low velocity but a high trajectory, and it was much more accurate and destructive than the ballista or catapult. It had a range similar to the catapult, if not a little greater.

One of the latterly adopted siege weapons of the Middles Ages was the cannon. In the 14th century, the technology was in its infancy so they were small and ineffective against walls. It was only in the 16th century did they become a force to be reckoned with.


What about the defenders?

What did the defenders have at their disposal? Well, they possessed the same siege weapons as the attackers: ballista, catapults, trebuchets, and cannons. Ballistae were usually placed atop towers and were used to target belfries and cats, as well as large groups of attackers. Catapults and trebuchets were normally found in courtyards and again used to destroy belfries and such.

Perhaps the most lethal of all weapons was something known as Greek Fire, which has been likened to modern-day napalm, though what it was actually made of has been lost to time. Probably a good thing. For fans of Game of Thrones, I imagine it’s one of the influences behind wildfire.  This, as well as other hot liquids, were dropped onto attackers.

This will give you an idea of what Greek Fire was like.


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