Concentric Castles

Concentric Castles

A concentric castle is a much larger construction than Motte and bailey or Stone keep castles. Concentric Castles, such as Beaumaris and Caerphilly Castles, make best use of angles in a castles design, providing the defender with more opportunity to hurt any attacking force. Essentially a concentric castle is a series of defensive structures. The typical design, as outlined in the image below, has two curtain walls, the outer one lower than the inner one. Each of the walls has a variety of rounded towers from which a defender has a number of vantage points over his assailant. In addition to the number of curtain walls and towers the castle was, usually, surrounded by water, making attack even more perilous.


Source A. Diagram of Beaumaris Castle.

Beaumaris Castle

Explanation of the diagram: to the outside is a large water obstacle. The first of the walls is a low curtain wall with a number of defensive towers; the inner wall was raised higher so that defenders would fire over the top of the outer wall. Once inside the outer curtain wall any intruder would be visible to archers or crossbowmen within up to 8 of the towers and along the walls. To successfully capture the castle they would also have to either scale both sets of walls, under fire from each of the towers, or breach the heavily fortified gatehouses.


(1) Why would attacking a Concentric Castle be harder than attacking a Motte and bailey or Stone keep Castle?
(2) Explain why the outer curtain walls were lower than the inner curtain walls.

Source B. Modern day image of an outer Curtain Wall at Caerphilly Castle.

The attacker would also have to penetrate a number of heavily guarded gatehouses, most of which had drawbridge entrances.


Major advantages of a Concentric Castle:

Round towers couldn’t be mined as easily.
Larger Castles can house a greater number of defendants.
Once inside the outer wall an attacker was still visible to defenders in a large number of towers.
The symmetrical design ensures that entry to the inner most parts of the Castle is closely monitored.
Low curtain walls mean that defenders on the inner and outer walls can see attackers.
A small number of men could defend a large part of the castle.


(3) Use the information in your textbook and previous notes to try and establish ways in which a concentric castle could have been attacked successfully. For each method of besieging a Castle try and find a solution to the problem in the design of Beaumaris Castle.
(4) Using the information on this sheet and in the resource packs made available to you, describe the defensive features of a concentric castle.
(5) Why was a Castle such as Beaumaris Castle such a formidable military structure?

CastlesPre-Norman FortificationsMotte and Bailey CastlesStone Keep CastlesConcentric Castles

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