Medieval castle walls, like other castle parts of the medieval castles, changed their structure over the centuries. During the early medieval times, the castle walls consisted of simple mud and stone fortifications which were inspired from earlier Roman structures. During the middle and late medieval ages, however, elaborate medieval castle walls were constructed which became the primary source of a medieval castles defence.
The most important purpose of a medieval castle walls was of course defence. During the time of enemy invasion, the medieval castle walls were used by the archers to shower arrows on the enemy. The castle walls were built wide enough so that the medieval castles military could easily walk around the walls to where the enemy was located, then the castles medieval archers and defending military units could fire arrows, and also pour boiling liquids and throw missiles such as rocks on the enemy.
Various mechanisms were used in the construction of medieval castle walls, as well as other castle parts, to make them more effective for defence. The walls were made thicker at the bottom to preclude the possibility of tunneling from the enemy. During the early medieval times, wood and heavy timbers called Palisades were also used for the construction of medieval castle walls. Further, the stones chosen for the construction of medieval castle walls were selected for their ability to withstand heavy blows and shocks. Holes were retained in the medieval castle walls which acted as arrow-loops.
Medieval castle walls were considerably thick and amongst the castle parts for defence, the most amount of resources were reserved for the construction of medieval castle walls. These walls were also known as curtains and their width varied from around 8 feet to 20 feet. The width largely depended on the terrain on which the castle was constructed. Similarly, the height of medieval castle walls also varied from castle to castle.
Various types of medieval castle walls have existed throughout medieval times. During the early medieval times, the most popular form of castle walls was made of wood and timbers. However, this changed after the Norman Conquest of England which gave rise to stone walls. Stone walls had obvious advantages that they were not susceptible to fire unlike wooden walls. Stones walls were also more resistant to attacks and blows by heavy weapons. A concentric castle which was probably the best defensive castle design of the medieval period had two layers of walls with the outer wall being lower than the inner one for defence purposes.
There were various castle parts that were built into medieval castles that became more advanced during the later medieval periods and were used to defend the medieval castle walls from attack. For instance, the medieval castle walls had arrow-loops which were vertical slits used to shoot arrows at the enemy. There were also Machicolations which were openings from the parapets constructed on the medieval castle walls. Heavy stones and boiling liquid could be thrown from these openings. On the outer side, the castle moat also served to protect the medieval castle walls.
Medieval castle walls become increasingly important defences for a medieval castle during the late medieval ages, particularly after the Norman Conquest of England. During the same period, concentric castles also became important which had outer and inner walls to provide for better defence. Various parts of the medieval castle walls were designed to provide effective protection for the castle. With the invention of Gunpowder and cannons medieval castles walls were unable to overcome this advancement in medieval weaponry and this combined with a new age of enlightenment “The Renaissance” was the beginning of the end of the medieval castle.