During Medieval times, it was common to construct castles and fortifications as a protection against enemy invasion. It was a common practice amongst kings all over the world to construct castles soon after conquering a country in order to solidify their hold on the new kingdom.
William the Conqueror had a string of castles constructed all over England after the Norman conquest of the country in 1066. Thus medieval castle defences played a very important role in the defence of the country and a kingdom with a batch of impenetrable castles had a clear edge over its enemies.
Like any defence mechanism, strategic locations were very important in medieval castle defences. The most important component in the defence was the location of the castle itself.
It was a common practice to construct the castle on high places such as mountain passes where it would be difficult for the enemy armies to attack. In actual defence, the walls of the castle served as the primary strategic location.
If the castle was located on plain land, it could be surrounded by a ditch of water known as a moat to provide a solid defence.
Various defence tactics or methods were used for medieval castle defences. For instance, it was common to construct castles of a circular shape that left no corners for miners of the enemy army to explore.
Another important tactic was to construct concentric castles with multiple walls which made invasion progressively difficult.
Finally, archers could shower arrows on the invading armies, stones, and hot liquids could be poured over the approaching enemy if the walls were thick and spacious enough to allow soldiers to walk around the Castle walls
Commonly battlements were built at the top of Castle walls
There were various defensive parts of castles that served as strategic locations during invasions. For instance, round towers were constructed because they provided a clear line of sight to the archers.
There were also slots built into castle walls that crossbowmen could fire bolts through. These slots were called arrow slits or loops and acted as an important component of medieval castle defence.
Among other defensive parts, there were also the holes around the castle entrances known as a murder holes which could be used to drop projectiles or burning liquids over the invaders. Many walled medieval towns had gatehouse entrances that contained murder holes.
During the early medieval ages, defending the castle was the responsibility of individual feudal lords who used their vassals to accomplish this.
This was true for the castles which did not have regular armies. In the case of the latter, soldiers were responsible for the defence. Eventually, however, paid soldiers were used everywhere for medieval castle defences.
The soldiers were usually commanded by a constable who was responsible for the medieval castle defences in the absence of the lord or higher ranking noble.
Various weapons were prevalent in medieval castle defences. The most important of these was the simple crossbow, considering the central role of archers in medieval castle defences.
One of the most important defensive devices designed during the high and late medieval period was a catapult which was used to defend castles as well as in attack during sieges.
Once a castle’s defences had been breached, a normal hand-to-hand battle ensued, and common weapons such as crossbows, longbows, swords, spears, and poleaxes were used as in common battlefield warfare.
Early medieval castles did not have the sophisticated defences of their later counterparts and were easier to attack and overrun, this led to constant improvements being made to keep pace with the advancements in medieval weaponry which led to all-around improvements in medieval castle defences.
In the later parts of medieval times with the invention of Gunpowder weapons such as Cannons Castles were fairly easy to destroy and the defensive walls could easily be destroyed, this and the new age of enlightenment at the start of the renaissance period led to the decline of Castles and this type of medieval warfare.