A view showing how the motte and bailey castle in Tonbridge, Kent, may have looked after it was erected by Richard Fitz Gilbert in the aftermath of the victory at Hastings. Mottes were not just a huge lump of earth but a carefully constructed structure and were usually built up in layers or around a rubble core where there was not an existing natural mound that could be used. They could vary from 50ft to over 100ft high and could have a diameter up to 300ft across. A timber palisade, a tall defensive wall made of vertical planks or logs, would have been erected around the keep or donjon on top. There is uncertainty as to the exact design of these buildings as evidence is sparse, mainly coming from stylised images on the Bayeux tapestry or descriptions from contemporary writers. It is likely they were simple timber structures in order to keep the weight down on the earthen motte and so they could be erected quickly by soldiers and local labour. Richard Fitz Gilbert’s original motte and bailey castle had a short life, as when the Conqueror died in 1087 he sided with his eldest son Robert, rather than the younger William. The latter however took the throne of England and besieged Richard’s castle at Tonbridge. After only two days, he stormed the defences and burnt it to the ground. The motte still survives today within the remains of the later stone castle.

Attackers fighting their way through the bailey while fire arrows rain down upon the tower on top of the motte. Defenders have draped fresh raw hides over the timber wall to reduce the chances of it catching fire.

Since ancient times, fire was used by attackers to destroy fortifications which contained timber structures. Lit torches or fires set up against a wooden wall were probably the earliest type of incendiary device. Flaming arrows were used in the medieval period as, even after castle walls were built of masonry, there was still wood in the roofs and floors of stone buildings and lesser timber structures within the enclosure. The arrow could have been crudely assembled with a strip of material soaked in pitch, oil or resin wrapped around the shaft. More sophisticated arrowheads were designed with metal cages for coal, wood shavings, cloth or similar materials soaked in oil, which were then lit and fired. A more potent weapon which struck fear into the hearts of defenders was `Greek fire’, a petroleum-based mixture which could not be extinguished with water. The knowledge for making this mixture (an early form of napalm) came via the Crusades to the Middle East in the 11th century where siege warfare was far more advanced than it was in Western Europe. Although the exact contents varied and its use was probably limited in this country, there are records of experts being paid to make Greek fire for attack on later stone castles. Richard I used some form of Greek fire when he was besieging Nottingham Castle in 1194 and pots were ordered to contain an explosive mixture during the siege of Stirling Castle in 1304. In 1340 at Tournai, France, Edward III’s forces employed a man who successfully created Greek fire to use against the defenders only for him to vanish without a trace after he had received payment in advance for more of his secret concoction.

When, in 1066, William, Duke of Normandy, sought to establish his right to the English throne, his first action after he crossed the channel was to build a castle within the old Roman fortification at Pevensey, Sussex. After the victory a short way along the south coast at Hastings, William was faced with the problem of having to control his new territory with an army and entourage which probably numbered around 20,000 in a country of 1,500,000 potentially rebellious Saxons. In order for such a limited number of Normans to hold key strategic points and also strike fear so that the native population would be reluctant to rise up against them, William had to quickly establish a network of castles.

William was of Viking descent and the title Norman is derived from Norseman. He had even brought some flat-packed fortified structures across the channel with him to speed up their construction. Many were built by his victorious barons on land William granted them in return for their loyalty. The first were erected along the coast to protect the landing points for his supplies and then as he pushed inland more were built to control valleys and river crossings. Some were also established in urban areas and many of these were purposely sited within existing fortifications, old Roman forts and Saxon burhs. He was not only saving time by reusing part of their defensive structures but also depriving the native population of a point from which to rebel. With these new imposing castles stamped upon Saxon towns and cities William was making it clear that he was in control and they would have to submit to his authority.

The new castles which were established across the country by William and his barons were usually of a motte and bailey design. This new type of fortification had evolved in Western Europe over the preceding century as kingdoms broke up into smaller units governed by nobles who needed a defendable home during these turbulent times. The bailey was a large enclosed area for the garrison, horses and supplies surrounded by a timber wall or palisade. It was overlooked by the motte, a tall mound upon which stood a timber lookout tower and refuge, known as the keep or donjon, which also provided accommodation for the noble or owner. The two were connected by gated bridge or steps which may have been removable in part at a time of trouble. The motte and bailey castle was a flexible form which could be adapted to the different sites. There were however, some occasions where a simpler form of earthwork was used. Ringwork castles, an enclosure formed from a defensive ditch, bank and palisades with the buildings erected within were often used, especially where there were existing fortifications or where a stone keep was planned which needed to be built upon a secure flat area.

These imposing fortifications made from wood and earth had the advantage that they could be built quickly as most men had the required building skills and the materials were readily available. The soil dug out when forming the ditches that surrounded the castle could be used to build up the bailey and the motte (the word motte was Norman for hillock). Timber for the structures could be sourced from the local area as well as from the houses and other buildings, which were often ruthlessly cleared off the site to make way for the castle. Although most buildings and walls were built from wood until the second half of the following century, in parts of the north and west stone was readily available and could have been used at an early date for some structures.

Attacking a Motte and Bailey Castle

The motte and bailey castle was a formidable obstacle for any army. The motte was designed with steep sides so it could not be scaled by men on horseback, and would be difficult for those on foot too. Some may have been covered in clay or timber to help protect the mound’s structure and make a surface which was harder to get a foothold upon. Thorn bushes could have also been planted to form a further barrier. It was the bailey which made the easier target for an attacking force and would be the first point where they would concentrate their efforts. Men with axes could hack at the timber palisades while shields or protective covers held off the defender’s arrows. In many cases the castle was simply stormed by a superior force who overwhelmed the defenders, attacking them with volleys of arrows, scaling the walls on ladders, and making their way through the castle with hand-to-hand fighting. When William II attacked rebels at Tonbridge Castle in 1088 he did not wait for machines to be built, but charged straight into direct action, taking the fortification within two days.

There was one weapon however which became the first choice for forces attacking a timber castle, and that was fire. Archers could shoot flaming arrows directly at the walls or aim higher and let them rain down upon the buildings behind them. Some arrowheads were designed with small oval-shaped metal cages behind the point specifically to contain natural fibres or cloth soaked in pitch for this purpose. William II’s brother, Robert of Normandy, ordered his bowmen to heat up the metal tips of their arrows in a fire until red hot and then shoot them onto the castle buildings. The defenders did not realise these arrows were setting fire to the roof until it was too late. The Bayeux Tapestry shows men setting fire to the timber palisades with firebrands on long poles so presumably this was a tried and tested method. There are also records of early attempts of making incendiary devices. A clay vessel filled with a mixture containing an inflammable substance like pitch, tar or animal fat was ignited and thrown at the walls, smashing on impact and forming a fire which would be hard for defenders to extinguish. These could have been dispatched by hand, thrown using a staff sling (a pole with a sling at the end) or by catapult. Geoffrey Plantagenet, the Count of Anjou and father of Henry II, became something of an expert in the use of fire and made an iron cauldron containing flax, seed and oil, which was heated up and thrown at the gates of the castle he was besieging so that it exploded on contact and set them on fire.

Defending a Motte and Bailey Castle

The defence of many castles began before an attacking army was in sight. The area around the outer walls could be cleared; this required demolishing houses and burning fields. The local drinking water could be poisoned and all good timber collected and stored inside the castle so the enemy could not use it. When the defenders of Wolvesey Castle, Winchester were preparing for an attack from the Empress Matilda in 1141, they burnt all the houses close to the walls which could give the enemy cover. In doing so they accidentally destroyed a large part of the old city. Carpenters and blacksmiths could also be forced inside the castle to help with making arms and also to ensure they were not available to assist the enemy.

With fire being the greatest threat, defenders could try and soak the timbers or drape fresh or wet animal hides over the palisades. The walls may have been coated in limewash or perhaps daub (a rendering made from clay, straw and other ingredients) in an attempt to make the timber more fire resistant. Water, sand, ash and earth may have been used by defenders to throw over any parts of the fortifications which had caught fire. If the enemy broke into the bailey then the garrison could retreat to the motte and destroy any bridge between the two, making an effective last stand. As the motte was on the outer edge of the bailey it also gave the defenders the chance to escape down the slope if all was lost. However, there was also the terrifying possibility that they could be trapped within a burning ring of fire, with any defenders trying to douse the flames picked off by archers.

Once the dispute was over, the crown had been settled and the new king Henry II had a firm grip over his kingdom, there began a great shift in the design of castles. Timber motte and bailey castles which had been erected without royal approval were demolished. Those which by the 1150s no longer served a military role were abandoned. Many fortifications which remained, especially those in the hands of the Crown or his wealthiest nobles, were extended and rebuilt. The revised fortifications had to adapt not only to the threat of fire as the knowledge of how to make and use it became more widespread, but also to the threat of new siege engines which could throw stones and smash timber palisades. Hence from the mid-12th century, castles were increasingly rebuilt in stone.