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The Rise & Fall of Castle Walls

The Romans first introduced the concept of fortified walls to defend their cities from invaders. These walls were made of stone and were often topped with battlements and watchtowers. As the Roman Empire crumbled, medieval Europe took over its architectural legacy. 

The castle walls of the Middle Ages were built to withstand siege and to intimidate and dissuade any potential attackers. These walls were thicker, higher, and more meticulously designed than their Roman counterparts. To improve the defensive qualities of the walls, additional defensive technologies such as crenellations, arrow slits, and murder holes were installed over time.

Purpose of Castle Walls

Castle walls were primarily built to defend the castle and its residents from attacks and intruders. During the Middle Ages, warfare was a constant threat, and these castle walls were a means of defending against it. 

Castle walls by Imfishy is licensed under CC BY-SA 4.0

Castle walls were also built to frighten and avert potential attackers. The height and thickness of the walls, as well as the presence of battlements, towers, and other defensive buildings, communicated that the castle was a well-fortified and well-defended bastion that could not be easily conquered. 

Types of Medieval Castle Walls (1)

Here are some of the different types of castle walls:

1) Curtain Walls

Curtain walls formed a crucial part of the defensive structure of a castle, encircling the entire complex and providing a first line of defense against potential attackers. These walls, usually the outermost layer, were designed to be extremely tall, reaching up to 30 feet or higher, making them difficult to climb over. Furthermore, the walls were constructed with a slight outward slope to increase their defensive capabilities. To further fortify the walls, towers were added along the curtain walls. These towers served as lookout points for defenders and added another layer of protection. 

2) Crenellations

Also known as embrasures, loopholes, or merlons, Crenellations were indentations or notches along the top of the wall. They provided cover for defenders while allowing them to shoot arrows or other projectiles through the gaps. The gaps between the merlons were known as crenels, and soldiers could stand in them to shoot at attackers. The alternating pattern of merlons and crenels created a strong defense.

3) Batters or Taluses or Plinths

A batter was a sloping surface on the face of a wall designed to provide stability and strength to the structure. Batters were often used in castle walls to help support the wall’s weight and prevent it from collapsing under the pressure of attacks, weathering, or settlement. A talus was a sloping surface at the base of a wall designed to deflect debris and protect the wall’s foundation. Taluses were often used in castle walls to prevent attackers from using the debris to undermine the wall’s foundation. A plinth was a flat, horizontal surface at the base of a wall designed to provide a stable foundation and protect the base from moisture and erosion. Plinths were often used in castle walls to prevent water from seeping into the foundation and causing damage. 

4) Hourdes

Hourdes were essentially wooden platforms projected from the top of the castle walls. They were supported by wooden brackets, known as corbels, which were built into the wall’s masonry. The primary purpose of the hordes was to provide a clear line of sight and a safe platform from which defenders could shoot arrows, throw stones, or pour boiling oil or water down on attackers. 

4) Machicolation

The name “machicolation” comes from the Old French word “machicoulis,” which means “a projecting work. Machicolations were typically located at the top of a castle wall or tower and consisted of a projecting stone or wooden structure with gaps or openings in the floor.  They were particularly effective against siege weapons such as battering rams and ladders, as they allowed defenders to attack from above without exposing themselves to enemy fire. 

5) The Brattice

The Brattice – A Brattice, also known as a bretèche or an oriel, is a projecting wooden or stone balcony or gallery that protrudes from the upper stories of a castle or other fortification. The purpose of a brattice was to provide defenders with an elevated position from which to observe and attack enemy troops who had breached the castle walls or gatehouse. In addition to providing an elevated position for archers and other defenders, brattices also had the added benefit of providing cover from arrows and rocks launched at the defenders from below.

Cannons and Concentric Castles (2)

Castle walls by S. Jiménez GB. is licensed under CC BY-SA 3.0 ES

The Concentric Castle represented the pinnacle of defensive fortification technology during the medieval era. With walls within walls and the outer wall being lower than the inner one, these castles were nearly impregnable to invaders. They could withstand long sieges, allowing defenders to repel even the most determined attacks.

Despite its impressive defensive capabilities, the Concentric Castle was not invulnerable. As gunpowder weapons, such as cannons, became more prevalent, they could easily penetrate even the thickest castle walls. With the emergence of gunpowder weapons, such as cannons, castle walls lost their status as military fortifications and became obsolete and ineffective for defense.


The invention of gunpowder weapons marked the end of the castle walls as effective military fortifications. As cannons became more prevalent, castle walls lost their status as impregnable defenses and became obsolete. However, medieval castle walls remain an important part of history and continue to fascinate people today.

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