A medieval castle was typically meant to serve a dual purpose. It was primarily a military fortification and very often, doubled as the private residence of the lord who owned it. Such dual-use directly affected the overall outlook and design of a medieval castle. Castle design also evolved significantly over the course of the medieval period.
In the early medieval period, castles were built in a more rudimentary fashion by erecting a keep on top of a mound of earth and then connecting the keep with a bailey which was situated at the bottom of the mound. Early Norman castles, for instance, followed this motte-and-bailey layout closely.
Later medieval castles came to integrate several new design elements such as the use of different kinds of towers, moats, barbicans, gatehouses, and even secret passages.
Early medieval castles, as built by Normans in Normandy and southern Italy before they took the trend to England in the 11th century, were typically motte-and-bailey castles. Such castles were designed to include two major elements.
One was the stone keep which was built on top of a steep mound of earth, giving it a highly defensible position. This keep was connected to a bailey at the bottom of the mound which comprised of a large piece of land enclosed within protective elements such as a ditch or barbican.
The residing lord took his residence at the keep while the soldiers, stores, stables, and other parts of the castle including the working peasants were located in the bailey. Such castle design proved military useful for Normans who used it as the backbone of their strategy to cement their control over England following the 11th-century conquest.
By the late medieval period, the designs of the castle had evolved significantly to incorporate many new elements. On one hand, the innovations pertained to the residential quarters which grew from being rudimentary to expansive and lavish.
On the other hand, the military aspect of the castles also developed significantly so that they came to incorporate new and formidable defensive elements. These included huge towers, an external curtain wall that rose to a significant height, and often an additional wall backing the curtain wall.
The gatehouses evolved from being a central point of entrance to an entry beset with numerous traps such as murder holes in case the attackers broke through the gates.
Huge towers were also added that housed military persons and were key points of defence of a medieval castle. These towers were carefully designed to make them one of the most defensible places within a castle.
Medieval castles differed significantly from one another in terms of their overall design. However, most of them included specific parts of the household.
These included, for instance, a courtyard within the residential quarters, towers along the external wall, a sizeable kitchen, a Great Hall for meals and feasts, a chapel and the priests’ quarters, a stable, and the residential quarters for military garrisons.