The Defensive Architecture of Medieval Castles

Each era in history has a form of architecture that defines it, that sticks in our mind more than any other, that we still visit today in order to learn more about our history. The Egyptians have their pyramids, the Greeks their temples, the Romans their arenas and so on. Medieval Europe has one type of building that stands out above all of its other constructions, an iconic form of architecture that is as fascinating as it was practical, this is none other than the castle. Castles were built to defend an area and every aspect of them had this in mind when designed, here are some of the fascinating features that were included to ensure nobody could get by these strongholds.

The Moat

When we talk about moats, we undoubtably imagine a circle of impassable water that surrounds these mammoth buildings, but this was not always the case. The moat was a deep ditch that circled the castle, making it difficult for attacker to approach the walls, of course some were filled with water making it even tougher to get near.

Arrow Slits and Battlements

The arrow slits are the thin straight openings in castle walls, these were simple yet extremely effective. The archer could fire through the slim gap with ease whilst have sufficient cover from incoming fire, a win-win situation for the defender. The battlements were more open however were designed with similar defensive capabilities in mind. The protective tooth shaped walls would again provide the archer with cover with the lower gaps giving them a space to attack from too.

Murder Holes

Murder holes are as insidious as they sound. Simply put these were holes built into the floors which lay above paths that attackers would no doubt have to use to enter the castle. Once the enemy passed under the defender could attack from these, throwing down debris, rubble and of course boiling oil. Often these would be places between two gates meaning you could trap your enemy between them and really do some damage.


Even the gates in castles could be used as a weapon, the portcullis was a huge gate on the castle entry usually made of wood or metal. These heavy doors had spikes across the bottom of them and were operated using chains. They could be dropped on intruders and would certainly take numbers out whilst causing a commotion. Whilst down they would protect the castle from battering and fire.


You may have noticed on visiting a castle that the stairwells are usually a spiral staircase, you may have also noticed that they always spiral in a clockwise direction. This is no accident but rather a very clever bit of design work. Most soldiers during these times would be trained to fight with a sword in their right arm and as an attacker you would usually find yourself fighting your way up these stairs. The stairs are designed to give the defender the advantage, having more room to operate their weapon as they descend the staircase.