Castle Siege *Attack & Defence

Castle Siege Attack

Castle Siege by Attrition

The aim of a castle siege using attrition tactics was to starve out the inhabitants of the castle by stopping food and water supplies from entering the castle, they would do this by blocking roads and also by poisoning any local water supplies.

Castle Siege by Attrition - Poisoning the Water Supply

This waiting game usually played out over days. weeks, months, and in rare cases up to a year, but generally no longer, as it would be difficult to maintain a castle for long periods of time without replenishing supplies.

Castle Siege by Attrition

There were also other factors to consider, like the disposal of human waste, illnesses, and diseases that could easily take hold without proper sanitation.
Castle Siege by Attrition - Diseases were common
It would be difficult for any castle to survive a long siege of attrition no matter how well-stocked and prepared the inhabitants inside the castle were at the outset, most castles’ sieges would be short-lived.

The combined effects of attrition and military attacks would be very effective against the inhabitants of a castle under siege, this would affect morale and cause anxiety as well as physical health to the inhabitants.

The castle’s inhabitants would be forced to eventually engage in combat just to get more food and water, usually, they would be in a weakened state due to the mental torture they had been under.

“A siege is a military blockade of a city or fortress with the intent of conquering by attrition or assault”

Medieval Castle Siege *Weapons & Tactics

besieging armies would use powerful siege engines known as Trebuchets to hurl large stones at the entrance and walls of the castle to bring them down. Flaming projectiles could also be thrown.

A Trebuchet Catapult Siege Attack on a Castle

Smaller catapults that were more maneuverable could be quickly positioned that also threw smaller rocks at the castle defenders on the top of the castle walls designed to injure or kill the castle defenders or its inhabitants.

Trebuchets and other catapults were also used to throw diseased animal and human bodies, and animal excrement was also thrown over the castle walls using these giant catapults with the aim of spreading disease and creating fear.

Trebuchet  Siege Engine

The Trebuchet was a giant throwing machine made of solid wood that could fire missiles up to a quarter of a mile at great speeds, large rocks would be thrown to destroy the walls and entrances of a castle, and the rocks thrown could also shatter into deadly splinters on impact.

Trebuchet Siege Engine - Castle Siege

The Trebuchet siege weapons also launched rocks and other projectiles to land inside the castle to kill and maim the scared the inhabitants, as well as this diseased human and animal corpses as well as excrement, could be launched into the castle to spread disease.

Trebuchet Siege Weapon


Attacking the Drawbridge

There were various ways and get into a castle via the main gate entrance and drawbridge, attackers could place large hooks attached to pulling machines called grappling hooks to pull down the drawbridge.

Medieval knights rushed to the entrance of castle

Deception techniques were also used, people would be disguised as someone who was known to or a friend of the castle, basically using a disguise to trick people into opening the drawbridge.

Surprising Castle Defenders

These attacks were sometimes used when there were good hiding places and opportunities to sneak into the castle unseen, invading armies would hide at night and then attack the castle by surprise often taking out guards on the castle walls by using archers.

Medieval Knights Defend a Castle


Undermining the Castle Walls

Some attacking armies used skilled miners called sappers during a siege to dig directly under the castle walls. These skilled miners would dig a tunnel under a section of the castle’s curtain walls, supporting earthworks were removed and replaced with thick wooden posts which allowed the miners to continue their work.

When the sappers (miners) had gone far enough under the wall they would exit and then set fire to the wooden posts that were now supporting the castle wall. This part of the castle wall would collapse when the wooden posts now supporting it gave way to the flames.

This was a very effective method of attack that allowed enemy soldiers to attack through the collapsed wall areas, however, mining techniques were not possible if the castle had a surrounding moat.


Castle Siege Battering Rams

Battering rams were used to ‘batter down’ the castle walls or gates. Battering rams were covered to protect the soldiers from enemy fire as they pushed them close to the castle walls or gates.

Using a built-in swinging mechanism the battering ram (usually a heavy tree trunk with a pointed metal encased tip) would be repeatedly slammed against a castle entrance (main gate) or walls.  Archers would also fire flaming arrows at the castle door, thus weakening the wood in the hope of making the battering rams’ job easier.

Battering Ram Rear - Castle Siege

Protected Battering Ram Rear


Castle Siege *Scaling the Walls *Ladders & Towers

Attacking soldiers would often use simple ladders to scale a castle’s walls, multiple ladders erected at the same time were more difficult to defend against.

Siege Tower

However, more sophisticated Siege towers were built to the same height as the castle walls, this siege equipment also protected the infantry soldiers’ as they advanced towards the top. attacking soldiers could also use grappling hooks to scale the walls.

Roman Siege Tower

Roman Siege Tower


Crossing the Castle Moat

besieging armies would sometimes lay planks of wood across the moat or set fire to the timber spikes that had been laid in defense of the castle in the case of a dry moat.

Medieval Castles Defences Moat

If the moat contained water sometimes armies would dig out channels with shovels that would create a channel to drain the water away from the moat so they could cross, although this would still be difficult to overcome because of the muddy conditions.


Mangonel *Smashing Castle Walls

A mangonel was a siege weapon that was commonly used to smash down castle walls, it was similar to the Trebuchet but was more specialised and designed to deliver great power at short distances. Using this castle siege weapon you could fire large stones at weak parts of a castle wall at very high speeds, this was a very efficient and destructive weapon.

Mangonel Siege Weapon


Besieging a Castle *Archers

Archers were very important infantry soldiers during a castle siege, they could fire thousands of arrows high into the air to come down on the inhabitants and defenders of the castle during a siege. Crossbowmen could take advanced positions, protected by large Pavise shields, and fire powerful bolts at defending troops on curtain wall battlements and gatehouses.

Pavise Shield

Archers called longbowmen could rapidly fire around 12 arrows a minute at castle defenders, whereas crossbowmen could fire powerful bolts at a slower rate. Archers’ arrow tips could also be covered in tar and set alight in the hope of burning down parts of the castle made from wood, and weakening areas such as the castle gate.

A Medieval Castle Being Defended Under Siege




Castle Siege Defence

The key to defending a castle against a siege was making sure the right decisions were made in the design and construction phases, before any seige even took place, such as building the castle in a great defensive location ideally on a hill with good all-round views for some distance.

An ideal location to build a castle was on high ground so that the defenders could see the enemy coming from miles away, being up a steep hill (ideally on a mountain top) would also make attacking the castle hard work and it would be very difficult if not impossible to transport heavy siege weapons such as battering rams and trebuchets to these locations.

Being on a steep hill will also make it difficult or near impossible for sappers (miners) to dig holes under the castle walls with the intention of collapsing them.

It was also essential to build the castle from the best materials available, eventually, all castles were built from stone and walls could be up to 6 meters thick, enough to protect them against catapults and other destructive siege weapon attacks.

High castle walls would also make it more difficult for attacking archers to kill defending soldiers on top of the castle walls, it also made it harder for besieging armies to use siege towers and ladders. An even better solution was to build a concentric castle that had walls within walls where defending soldiers could re-group if the outer wall was breached.
medieval concentric castle parts

Concentric Castle

Food Supplies

Another key factor when preparing for a siege was to make sure that there were plenty of supplies, with food, water, and enough weapons to fight off attackers being the key to defending a castle from a besieging. If you had enough food and water during a siege you might be able to outlast the attackers before you starved.


Pulling up the Drawbridge!

In defending the castle it was always essential to pull up the drawbridge quickly, a castle moat was commonly filled with water or if it was a dry moat spikes were often used, this would protect the castle entrance from attack, and stopped battering rams, battering down the castle entrance.

There were also commonly large wooden and metal bars that would slide horizontally across the back of the castle gate, which would add additional strength to it and make it harder to break down. The gate was further strengthened by a metal or wooden portcullis.

Portcullis Drawbridge Counterweight

Barricading the Entrance

One of the tactics used during a siege was lower the portcullis and barricade the entrance, built into most castle designs were also “murder holes” which allowed the pouring of boiling oil or water onto the attacking soldiers in relative safety from above.

Bodiam Castle Murder Holes

Bodiam Castle Murder Holes

Was Attack the Best Defence During a Siege?

In many situations, it could be a good idea to take the initiative away from the attacking army by sending your best men at arms on a quick surprise attack from the castle to either destroy the enemies’ siege weapons or take out important enemy units.

Sometimes castle troops would have to be sent on daring missions for supplies or to muster help. Often a surprise nighttime raid could do plenty of damage and leave the besieging army in disarray.

Medieval Knights Weapons

Counter Attacking Siege Tunnels

Counterattack tunnels could be mined to meet up with the tunnels mined by the attacking sappers, the captured sappers could then be put in the castle’s dungeon, this stopped these skilled miners from being able to collapse the castle’s walls.  The tunnels could also be collapsed on the miners as they worked.

Castle Moat Defence

It was a good idea to fill a moat with either water or spikes to slow down a siege on a castle, the castle moat might also be filled with excrement which would discourage the enemy from wading or swimming across. The Castles moat would also stop attackers from mining under the castle walls and would stop an enemy from using siege towers as they would be unable to push them up against the castle walls.

Natural Moats where a castle was built on an island for example were commonly wider and deeper than man-made moats.

Firing Back

Soldiers defending a castle would use any projectile they could to injure and maim attacking forces, rocks were thrown, boiling oil and water poured, and arrows and bolts were fired from battlements, murder holes, arrow loops, and other defensive parts of the castle.

Castle Arrow Slit Inside

Castle Arrow Slit or Arrow Loop

Defending Against Siege Towers & Ladders

Another simple defensive tactic that was used to fight back against besieging armies was to simply push the ladders away from the castle walls. Hot oil or water could be poured onto the enemy’s forces through murder holes. Oil could also be poured onto siege towers and ignited with tar-tipped arrows fired from the castle’s archers.

Castle Sieges End

It must have been a very scary event to be inside a Castle during a siege as you could see the size of the enemy as they advanced, however, if you were well prepared and had plenty of food and water you had a much better chance of survival.
Medieval Gunpowder Weapons

Medieval Gunpowder Weapons

As technology improved towards the later parts of the medieval period, cannons and other weapons were introduced and a castle no longer offered the same protection as it had in the past, this is the main reason why castles became a thing of the past and became used for residential and historical purposes only, as a reminder of our great medieval history.