CASTLES OF GREAT BRITAIN

Early Castles:

From as early as late Neolithic times (Between 8500 B.C.-2500 B.C.), people built hill forts to protect themselves. Many earthworks survive today, along with evidence of the use of palisades to accompany the ditches. The Romans commonly encountered hill forts (called oppida) built by their enemies. Though primitive, they were often effective and required extensive siege engines and other siege warfare techniques to overcome, such as at the Battle of Alesia.

Their own fortifications (castra) varied from the simple temporary earthworks thrown up by armies on the move, to elaborate permanent stone constructions, notably the milecastles of Hadrian's Wall. Plans for Roman forts were generally rectangular with rounded corners.

The Roman engineer Vitruvius was the first to note the threefold advantages of round defensive towers; more efficient use of stone, improved defence against battering rams and improved field of fire. It was not until the 13th century that these advantages were rediscovered.

Roman fortifications, or, when possible or needed, other edifices, were often turned into castles or similar structures during the early Middle Ages. A famous example is that of the Hadrian's Mausoleum in Rome, which is known to have been used as a fortress as early as 537, during the Gothic War. Other Late antiquity-early Middle Ages castles are known in Brescia and Trento in Italy, Saint-Blaise in Provence and Büraburg and Glauberg in Hesse, the latter probably built by the Alemanni. In Spain, king Liuvigild founded a powerful fortress called Reccopolis in 578, and also the 7th century fortress of Puig Rome, near Girona, has been excavated. At Selinunte, in Sicily, the Byzantines turned two ancient temples into a simple fortress (7th-8th centuries): several centuries earlier, emperor Justinian I is known to have promoted a large program of castle building.

Wooden castles: Motte-and-bailey:

The earliest recorded structures universally acknowledged by historians as 'castles' were built of earth and wood in Northern France Circa the late 9th century.

The essential feature of this type was a circular mound of earth surrounded by a dry ditch and flattened at the top. Around the crest of its summit was placed a timber palisade, with a wooden tower in the middle.This moated mound was styled in Old French motte (Latin mota), a word still common in French place-names. In addition to the mound, a bailey or basse court of horseshoe shape was usually appended to it, so that the mound stood on the line of the enceinte. The latter housed the domestic quarters, stables, stores, a forge and a water well. These earthworks were dug from the perimeter area, leaving a defensive ditch. In many cases the motte seems to be a later addition to an already existing wooden settlement, surrounded by a wood palisade.

A description of this earlier castle is given in the life of St John, Bishop of Terouanne: “ The rich and the noble of that region being much given to feuds and bloodshed, fortify themselves ... and by these strongholds subdue their equals and oppress their inferiors. They heap up a mound as high as they are able, and dig round it as broad a ditch as they can ... Round the summit of the mound they construct a palisade of timber to act as a wall. Inside the palisade they erect a house, or rather a citadel, which looks down on the whole neighbourhood. ” John died in 1130, and this castle of Merchem, built by a lord of the town many years before, may be taken as typical of the practice of the 11th century.

Construction of new castles is attested from the Carolingian era, but their construction seems to have been related mainly to the defence of frontiers and of the main statal properties: the right to build such a structure was in fact a royal privilege. However, changes took place from the late 9th century, probably under the pressure of raids by the Vikings and Magyars, but also due to the general uncertainty of the crumbling of the Carolingian Empire. As early as 864, Charles the Bald issued an edict ordering the destruction of all the private structures erected without his permission. Hundreds of motte-and-baileys are known from north-western France, from whence they spread into Germany. There was frequent fortification of cities, monasteries, ports and rural settlements in this period. In 906, a diacon in Verona asked Berengar I of Italy for the permission to built a castle in Nogara "due to the heathens ravages".

The pagans, however, were not the sole threat leading to edification of castles: in 920, the Bishop of Adria received the permission to erect a fortress in Rovigo to "save the people either from the heathens and from evil Christians". Henry I of Germany built a series of fortresses to protect the frontier west to the Rhine: a notable example is that of Werla, in Saxony, erected in 926 as a defence against the Magyars. This consisted in a circular wooden wall, already existing in the 9th century, which the king had surrounded by a stone wall with two gates.

Factions struggling for powers in the lack of the supreme authority were in need of military fortresses, but also of a visible show of their growing power over the surrounding population. When William the Conqueror executed the Norman Conquest of England, he brought with him the practice of building a castle to protect and hold the land, by then quite familiar on the mainland of western Europe. They were an intrinsic element of his strategy of conquest, and the original castle he built at Pevensey was brought across as a prefabrication, a detail revealed by the Bayeux Tapestry. The Norman kings and their barons constructed a plethora of castles to impress, control, and conquer the native population. Lewes Castle, built by Gulielmus de Warenne, is an unusual example, as it featured two mottes. Wooden castles were built up until the 12th century.

During the 11th century Investiture Controversy in Germany and the resulting decline of the royal power, castle-building exploded as local warlords staked claims to formerly royal prerogatives in their petty states. This proliferation of castles, which made them iconic of the Middle Ages, is called "encastellation". Around the year 1100 there were in Europe thousands of castles, belonging to bishops, abbots, marquesses, counts, often small size structures erected by petty lords to mark their new conquest of a small, though prestigious (and sometimes ephemeral) power. The construction and restoration of these structure, as well as the maintenance of the garrisons, was a task of the population, which in exchange obtained the possibility to take shelter within the walls in case of peril. According to Christopher Gravette, "the castle was not just a fortress, it was also the residence of its lord".

Stone structures:

Although a minority, stone fortifications had also been built during the whole early Middle Ages. Sometimes Roman walls and ruins were re-used, as is the case at Portchester Castle, where a square Norman keep sits in the corner of a Roman fort. The most ancient surviving example is the tower at Doué-la-Fontaine, built circa 950 in northern France: these castles centered around the donjon took more time and investment to build than wooden castles, but were more fireproof and secure.

They could also be built as a mix of timber and stone, and sometimes stone buildings were built on existing mottes. When a stone wall replaced the timber palisade of the existing structures, it produced what is known as a "shell-keep"; the type met with in the extant castles of Berkeley, Alnwick and Windsor in England. In southern Europe stone castles became predominant from the mid-11th century, spread by the Norman conquests; the same occurred in the Holy Land through the Crusades, although Islamic and Byzantine influences were also present. In Germany, the equivalent of the keep was called the Bergfried.

The Normans introduced two other types of castle. The one was adopted where they found a natural rock stronghold which only needed adaptation, as at Clifford, Ludlow, the Peak and Exeter, to produce a citadel; the other was a type wholly distinct, the high rectangular tower of masonry, of which the Tower of London is the best-known example, though that of Colchester was probably constructed in the 11th century also. But the latter type belongs rather to the more settled conditions of the 12th century when haste was not a necessity, and in the first half of which the fine extant keeps of Hedingham and Rochester were erected. These towers were originally surrounded by palisades, usually on earthen ramparts, which were replaced later by stone walls. The whole fortress thus formed was styled a castle, but sometimes more precisely "tower and castle", the former being the citadel, and the latter the walled enclosure, which preserved more strictly the meaning of the Roman castellum.

Reliance was placed by the engineers of that time simply and solely on the inherent strength of the structure, the walls of which defied the battering ram, and could only be undermined at the cost of much time and labour, while the narrow apertures were constructed to exclude arrows or flaming brands. The Alcazar of Segovia in Spain.

In the 11th century fortification architecture was also prominent in Islamic countries. Fortress there, when possible, took advantage of the terrain characteristics, and the walls were intervalled by flanking towers with, sometimes, a detached towers (albarrana). During the Spanish Reconquista, a keep (torre del homenaje, Tower of the homage) was added by the Christians when they captured these castles, as it happened for the castle of Banos in 1212.

Concentric and linear castles:

At this stage the crusades, and the consequent opportunities afforded to western engineers of studying the massive constructions of the Byzantine Empire, revolutionized the art of castlebuilding, which henceforward follows recognized principles. The Byzantines did not build large stand-alone fortresses, but their largest cities, especially on the traditionally dangerous Eastern frontier, had enormous fortifications. The First Crusade took (more by treachery than assault) the very well fortified city of Antioch, and many other Byzantine fortifications that had fallen into Muslim hands. The crusaders were used to castles, and also needed to defend key points in their new territory. They were also extremely short of fighting men, whilst they had generally good supplies of labour and cash for construction. Their enormous castles, many in isolated strategic spots, and designed to be normally very thinly garrisoned, were the result. Of these Krak des Chevaliers was the largest.

Many castles were built in the Holy Land by the crusaders of the 12th century, and it has been shown that the designers realized, first, that a second line of defences should be built within the main enceinte, and a third line or keep inside the second line; and secondly, that a wall must be flanked by projecting towers. From the Byzantine engineers, through the crusaders, we derive, therefore, the cardinal principle of the mutual defence of all the parts of a fortress.

The donjon of western Europe was regarded as the fortress, the outer walls as accessory defences; in the East each envelope was a fortress in itself, and the keep became merely the last refuge of the garrison, used only when all else had been captured. Indeed the keep, in several crusader castles, is no more than a tower, larger than the rest, built into the enceinte and serving with the rest for its flanking defence, while the fortress was made strongest on the most exposed front. The idea of the flanking towers (which were of a type very different from the slight projections of the shell-keep and rectangular tower) soon penetrated to Europe, and Alnwick Castle (1140-1150) shows the influence of the new system.

In Richard Cœur de Lion's fortress of Château-Gaillard Les Andelys, the innermost ward was protected by an elaborate system of strong appended defences, which included a strong fte-de-pont covering the Seine bridge. The castle stood upon high ground and consisted of three distinct enceintes or wards besides the keep, which was in this case merely a strong tower forming part of the innermost ward. The donjon was rarely defended until the very end and it gradually lost in importance as the outer "wards" grew stronger. Frederick II's Castel del Monte in Puglia has no keep at all: rising on a strategic alture, it consist of an octagonal structure with eighth polygonal, massive towers.

Round instead of rectangular towers were now becoming usual, the finest examples of their employment as keeps being at Conisborough in England and at Falaise and Coucy in France. Against the relatively feeble siege artillery of the 13th century a well built fortress was almost proof, but the mines and the battering ram of the attack were more formidable, and it was realized that corners in the stonework of the fortress were more vulnerable than a uniform curved surface. Château Gaillard fell to Philip Augustus in 1204 after a strenuous defence, and the success of the assailants was largely due to the wise and skilful employment of mines. An angle of the noble keep of Rochester was undermined and brought down by King John of England in 1215.

The next development was the extension of the principle of successive lines of defence to form what is called the "concentric" castle, in which each ward was placed wholly within another which enveloped it; places thus built on a flat site (e.g. Caerphilly Castle) became for the first time more formidable than strongholds perched upon rocks and hills such as Château Gaillard, where the more exposed parts indeed possessed many successive lines of defence, but at other points, for want of room, it was impossible to build more than one or, at most, two walls. In these cases, the fall of the inner ward by surprise, escalade, vive force, or even by ordinary siege (as was sometimes feasible), entailed the fall of the whole castle. The adoption of the concentric system precluded any such mischance, and thus, even though siege engines improved during the 13th and 14th centuries, the defence, by the massive strength of the concentric castle in some cases, by natural inaccessibility of position in others, maintained itself superior to the attack during the latter Middle Ages.

Construction of castles in this period was often connected to the necessity to establish a strong central power against local fragmentation, or in newly conquered lands: examples are the large buildings programs of Edward I of England in Wales, Philip I August of France, the Ezzelino IV da Romano and the Scaligers in northern Italy, Frederick II and Charles I of Anjou in southern Italy (often reusing former Norman or even Byzantine and Lombard structures), King Denis I in Portugal, and notably the Teutonic Knights in their conquest of Pagan lands in Prussia and Poland. In Germany, stone structures appeared in Hesse, Thuringia, Alsace and Saxony, commissioned by the powerful local aristocracy. Structures in northern Germany were usually simpler, often taking advantage of water streams.