By George Ghidrai

If we are asked to visualize a castle, most of us will come with the image of a grand building made up of stone, with several towers and an impressive keep, a massive gatehouse, battlements with arrow slits, and a deep moat surrounding the entire edifice.

However, the original castles were far removed from that romantic image.

The Motte-and-Bailey Castles - a huge success

The motte-and-bailey castle was a true European innovation. While the concept of ditches, ramparts, and stone walls as defensive measures is ancient, raising a motte is a medieval innovation.

Originally, these castles were constructed from timber and earth alone; they were cheap and easy to build and didn't require any special design. The fortification consisted of a wooden keep that was placed on a raised earthwork called a motte, overlooking an enclosed courtyard called the bailey.

Motte and Bailey Castle

As we can see, these castles included three main design elements:

The Motte The Motte (the word derives from Old French) was a large earthen mound with a ditch surrounding its base. It was often artificial, meaning it had to be built by piling up earth, but sometimes it incorporated a pre-existing feature of the landscape, such as a nearby hill. Large mottes could be as high as 30 meters and as large as 90 meters in diameter, but they were rarely used. That's because it took an enormous effort to pile up such a huge volume of earth. The motte was flattened on top to make place for the wooden keep. The steep embankment on the side of the motte was known as a Scarp.

The Keep The keep on top of the motte was the castle's primary defensive element. It was surrounded by a protective wall, originally made of wood. Small mottes could only support a simple tower but larger mottes could support more complex structures that often contained multiple rooms. The keep on top of the motte was the castle's last line of defense and it was the place where the lord of the castle (together with his wife) inhabited. Larger towers were often equipped with cellars and granaries, more living rooms and rooms for the watchmen and the servants appointed to keep the house. It was not uncommon for the tower to be built and then partially buried within the mound, with the buried part forming a cellar.

The Bailey The term bailey refers to a yard formed by flattening an area alongside the motte. The yard was surrounded by a wooden fence called a palisade and then a ditch. The bailey was the center of domestic life within the castle and could contain a variety of buildings, including halls, kitchens, stores, stables, a chapel, barracks, and workshops. The bailey was linked to the motte either by a flying bridge stretching between the two, or, more commonly in England, by steps cut into the motte. Sometimes, the ditches were filled with water by damming or diverting nearby streams forming water-filled moats.

A more detailed diagram of a Motte and Bailey Castle

In practice, no two motte-and-baileys were exactly the same although most of them shared these three common elements.

For example, a castle could have had more than one bailey and a good example is Windsor Castle where several baileys flank the motte. Alternatively, some castles were designed with a single bailey and two mottes, such as Lincoln Castle. Fundamentally, the design of each castle adapted to its natural surroundings.

Aerial view of Windsor Castle. We can see the two baileys (left and right) flanking the original motte in the middle

Why were motte-and-baileys so popular?

Motte-and-bailey castles were immensely popular for nearly 200 years. The Normans were huge advocates of this type of castle design and we have already learned that motte-and-baileys were a decisive factor in the Normans successful conquest of the British Isles.

Despite the simple and relatively rough design, motte-and-baileys had excellent defensive capabilities. Attackers soon found out that the keep on top of the motte was surprisingly hard to capture as the height of the motte and the ditch surrounding it gave defenders a significant defensive advantage.

Moreover, Norman designers found that the wider the ditch was dug, the deeper and steeper the sides of the scarp could be, making life even more difficult for the attackers.

The biggest advantage of the Motte and Bailey design was how extremely cheap and easy to build it was. Designers could use an existing mound or hill for foundations which could save significant construction time.

Construction didn't require any special materials, and the work could usually be carried out by unskilled men. This meant that a motte-and-bailey castle could be built relatively quickly using local manpower and earth and timber alone as building materials. This allowed the Normans to quickly consolidate their power, then move on and conquer the next region.

As a marker of their success, almost 1,000 motte-and-bailey castles were built in England, Wales, and Scotland.

Although the motte-and-bailey design is a particularly northern European phenomenon (most castles of this type can be found in Normandy and Britain), we can also see such structures in other parts of Europe, such as Denmark, Germany, Southern Italy and occasionally beyond.

Motte-and-baileys decline

By the end of the 11th century, motte-and-bailey castles (especially those made entirely out of earth and timber) began to fall from favor. There were several reasons behind this fact.

One thing that made the motte-and-bailey design so popular was the use of wood as the primary building material, however, this also became the design's Achilles heel. Because timber burns easily, firing flaming arrows at the castle could have devastating consequences.

Sophisticated fire-launching techniques designed to burn down the castle were developed and used with great success.

Moreover, the broad base of the mottes meant that attacks could come from any direction, and raiders were quick to use this to their advantage, often surprising the defenders inside the keep.

Timber also tends to rot easily, and many of these early castles quickly ran into disrepair and were often abandoned or required significant (and often expensive) repairs and ongoing maintenance.

Small and medium mottes could not sustain a large keep, and this meant that living quarters were usually small and cramped. There was little space to house soldiers and peasants, let alone provide the stature yearned for by many nobles.

To build a large tower that could properly accommodate the lord and his servants, castles needed a large motte. However, a large motte was extremely difficult to build as it took disproportionately more effort to pile up the earth than in the case of smaller hills. As an example, a large motte is estimated to have required up to 24,000 man-days of work while smaller ones required perhaps as little as 1,000.

The cost of this design was not easily scalable and the reality of the times forced local nobles to forego the simple motte and bailey design and turn to more complex design principles to build the large castles that their status and people needed for economics, politics, and defense. To avoid the perils of fire, improve durability and increase the castle defense capability, the obvious solution was to replace (wherever possible) timber with stone.

Chateau de Gisors in Normandy, a perefect example of a motte-and-bailey castle, where the wooden tower was replced with a stone keep

What happened to the motte and bailey castles?

The Motte-and-bailey design became less popular in the mid-medieval period, and from the end of the 12th century, a new scientific approach in castle design had emerged. And with this new approach, the great era of stone castles had begun.

Some motte-and-bailey castles were abandoned or allowed to lapse into disrepair; those with wooden keeps rotted away, leaving a handful of odd shaped hills scattered across the landscape as the only indication they ever existed.

Not all were abandoned however, with many of these original motte-and-bailey castles used as foundations for the newly designed stone castles.





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