Amazing Places

These Are the Brilliant Defense Mechanisms of Medieval Castles

Picture this: it's the Middle Ages, and you're one of the lucky few that gets to call a castle home. Unfortunately, the problem with owning a castle is that they're pretty tempting for other people who own castles. If you want to protect what's yours, you've got to go way beyond thick walls and deep moats. Here are the features your fortifications will need.

Swing for Defenses

The thing about defending against a siege is that you have a lot more to worry about than whether your walls can withstand the catapults. There are a number of different weapons that your attackers might bring against you, and you would have to design your castle with defense against each in mind. Here are some of the threats you'd face, and how you might do so.

  • Motte and bailey: If you were wandering England between the 9th and 11th centuries, you might not have recognized the castles as such. They weren't even stone, just wood and thatch. But they followed a basic plan known as "motte and bailey," which would remain popular for centuries afterward. The motte is a hill, artificial or otherwise, with the main fortress on top. The bailey is an enclosed field down below, which would give archers on the motte free reign to fire on any rampaging attackers.
  • Moats: One of the defining features of a motte and bailey was a ditch surrounding the motte, which would make it even more difficult to scale. Sometimes, this ditch would be filled with water to make it even trickier. Eventually, the word "motte" transformed into the word "moat." The moat could shape the battlefield, and would work in concert with other defensive features.

  • Barbican: Because of the moat (along with chokepoints such as drawbridges and portcullises), defenders can be pretty certain of which parts of the castle will get the most attention from attackers. That's where the barbican comes in. It can take many forms, but its basic function is to tower over chokepoints and make the people stuck there regret their decisions. From high above the gate or bridge, defenders inside the barbican could rain down arrows and worse.
  • Arrowslits and murderholes: Two of the most common features of the barbican would be arrowslits and murderholes. Although they were technically invented some time around 200 B.C.E., arrowslits fell out of style until about the 12th century C.E. Because of their narrow shape, they would allow defenders to fire freely without leaving much of a target to aim for. Even more insidious were the murderholes, also known as machicolations. From these holes in the floor directly above well-trod assault paths, defenders could hurl down refuse and debris, and even boiling oil.
  • Elevated doorways: Walls and moats and murderholes are a great way to keep ground troops from getting through your door. So is keeping your door high off the ground. While other defensive features have gotten more attention, elevated doors are almost a universal feature of castles everywhere. But how do you use a door that's 12 feet (4 meters) off the ground? Simple — in peacetime, those doors had removable wooden stairs and ramps leading up to them.

Location, Location, Location

Probably the most important feature of your medieval castle would have to be determined before the first foundation was laid — its natural surroundings. Dover Castle, which you can still visit today, is an example of one that took great advantage of its location. Perched at the top of the region's famous White Cliffs, it was incredibly difficult to besiege by land or by sea. That fact proved vital to the history of England in the early 13th century when France attempted to take the castle while the barons and King John were wrapped up with the fallout of the Magna Carta. Besides its elevated location, the castle also employed design strategies such as concentric walls, which could stave off trebuchets. Over the course of the next couple centuries, the castle's fortifications only grew. It's proof that the strongest castles were the ones that could adapt to the world around them.

There's so much to learn about how the various parts of a castle all fit together. Check out the critically acclaimed, fully illustrated "Castle" by David Macaulay (best known as the writer and illustrator behind "How Things Work"). We handpick reading recommendations we think you may like. If you choose to make a purchase through that link, Curiosity will get a share of the sale.

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Written by Reuben Westmaas May 24, 2018

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