For centuries, castles, or fortified buildings, were instrumental in defence. In Europe, the popularity and unrivalled defensive power of castles persisted throughout what is known as the Medieval period. There are many different castle designs, as castle construction needed to be suited for the materials of the region as well as the defensive possibilities of the landscape, but many of them fit into three basic types of castles found in Europe.
Motte and Bailey
A motte and bailey is one of the most basic types of castle, and, as one might deduce from the name, consists of a motte and one or more baileys. A motte is a hill or mound, usually artificially created, with a wooden keep or lookout at the top. This building was surrounded by a wooden fence, called a palisade. A bailey is a courtyard below the motte. The bailey was where the inhabitants of this kind of castle lived, and was protected by a fence, as well. The entire motte and bailey could also be protected by a ditch or moat.
A stone keep is a plain stone building, superior to the motte and bailey for defence in large part because it is made from stone, and so difficult to set on fire. Stone keeps also had an advantage in that they could be built much higher than a motte and bailey, adding to visibility, and could have thicker, stronger walls. These keeps had few windows, which were very small, and the main entrance to a keep was on the second floor to make it difficult for enemies to enter. A stone keep was surrounded by a wall, also made from stone, which had turrets for lookout purposes. Early stone keeps were rectangular, and many later ones were circular.
A concentric castle was the pinnacle of defence in medieval times. These castles consisted of a wall within a wall. The walls were designed to have many points at which an invading army could be trapped, as well as multiple keeps and lookouts. For instance, concentric castles were often surrounded by a moat, and the point of entry was a drawbridge, which greatly limited the ability of an army to invade. Drawbridges, barbicans, moats, murder holes and death traps are all classic features of the defences of a concentric castle. Concentric castles also had advantages that are less obvious but extremely important, such as plumbing. This reduced the ability of an enemy to poison a water supply.
At the rise of the cannon as a weapon of war, the effectiveness of castles for defence declined. The most well-designed castle could be demolished by cannons quite readily. Over time, the building techniques and designs of castles became converted to building lavish living quarters for the wealthy and powerful, as these designs lent themselves to housing large numbers of people. Palaces were built during the decline of castles, and while they are similar, they were built for housing purposes rather than defensive purposes.