Editing Keep (section)

===Early stone keeps (10th–12th centuries)===
{{Multiple image|direction=horizontal|align=right|image1=Colchester castle 800.jpg|image2=Colchester Castle Keep.jpg
|width=250|caption2=|caption1=The Norman keep at [[Colchester Castle]] in Essex, built in a [[Romanesque art|Romanesque]] style on the foundations of a Roman temple}}
During the 10th century, a small number of stone keeps began to be built in France, such at the [[Château de Langeais]]: in the 11th century, their numbers increased as the style spread through Normandy across the rest of France and into England, South Italy and Sicily.<ref>Nicholson, p.78; Kaufmann and Kaufmann, p.109.</ref> Some existing motte-and-bailey castles were converted to stone, with the keep usually amongst the first parts to be upgraded, while in other cases new keeps were built from scratch in stone.<ref>Brown, p.38.</ref> These stone keeps were introduced into Ireland during the 1170s following the Norman occupation of the east of the country, where they were particularly popular amongst the new Anglo-Norman lords.<ref>McNeill, pp.20, 53.</ref> Two broad types of design emerged across France and England during the period: four-sided stone keeps, known as Norman keeps or great keeps in English – a ''donjon carré'' or ''donjon roman'' in French – and circular [[shell keep]]s.<ref>Viollet-le-Duc, p.77.</ref>{{refn|Although medieval writers typically referred to Norman keeps as a ''magna turris'', or ''great tower'', there was no specific contemporary term for a [[shell keep]].<ref>Hulme, p.214.</ref>|group=nb}}

The reasons for the transition from timber to stone keeps are unclear, and the process was slow and uneven, taking many years to take effect across the various regions.<ref name=Brown1962P36>Brown, p.36.</ref> Traditionally it was believed that stone keeps had been adopted because of the cruder nature of wooden buildings, the limited lifespan of wooden fortifications and their vulnerability to fire, but recent archaeological studies have shown that many wooden castles were as robust and as sophisticated as their stone equivalents.<ref>Brown, p.36; Toy (1985), p.54; Creighton and Higham, pp.41–2.</ref> Some wooden keeps were not converted into stone for many years and were instead expanded in wood, such as at [[Hen Domen]].<ref>Creighton and Higham, p.41.</ref> Nonetheless, stone became increasingly popular as a building material for keeps for both military and symbolic reasons.<ref>Liddiard (2005), p.53; King, p.62.</ref>

Stone keep construction required skilled craftsmen. Unlike timber and earthworks, which could be built using [[unfree labour]] or serfs, these craftsmen had to be paid and stone keeps were therefore expensive.<ref name=Pounds1994P20>Pounds, p.20.</ref> They were also relatively slow to erect, due to the limitations of the [[lime mortar]] used during the period – a keep's walls could usually be raised by a maximum of only 12 feet (3.6 metres) a year; the keep at [[Scarborough Castle|Scarborough]] was not atypical in taking ten years to build.<ref name=Pounds1994P20/> The number of such keeps remained relatively low: in England, for example, although several early stone keeps had been built after the conquest, there were only somewhere between ten and fifteen in existence by 1100, and only around a hundred had been built by 1216.<ref>Hulme, p.213.</ref>

{{Multiple image|direction=horizontal|align=left|image1=Goodrich Castle keep1.jpg|image2=Goodrich keep plan alternative.jpg
|width=190|caption1=|caption2=The Norman keep (r) and prison (l) at [[Goodrich Castle]] in [[Herefordshire]], England, built to a square design in the early 12th century}}
Norman keeps had four sides, with the corners reinforced by [[pilaster]] [[buttress]]es; some keeps, particularly in Normandy and France, had a ''barlongue'' design, being rectangular in plan with their length twice their width, while others, particularly in England, formed a square.<ref>Toy (1985), p.66; Baldwin, p.298.</ref> These keeps could be up to four storeys high, with the entrance placed on the first storey to prevent the door from being easily broken down; early French keeps had external stairs in wood, whilst later castles in both France and England built them in stone.<ref>Toy (198), p.66; King, p.67.</ref> In some cases the entrance stairs were protected by additional walls and a door, producing a forebuilding.<ref name="King">King, p.67.</ref> The strength of the Norman design typically came from the thickness of the keep's walls: usually made of [[rag-stone]], these could be up to 24 feet (7.3 metres) thick, immensely strong, and producing a steady temperature inside the building throughout summer and winter.<ref>Brown, p.45; King, p.68.</ref> The larger keeps were subdivided by an internal wall while the smaller versions had a single, slightly cramped chamber on each floor.<ref>Brown, p.46; Thompson (2008), p.65.</ref> Usually only the first floor would be [[vault (architecture)|vaulted]] in stone, with the higher storeys supported with timbers.<ref name="King" />

There has been extensive academic discussion of the extent to which Norman keeps were designed with a military or political function in mind, particularly in England. Earlier analyses of Norman keeps focused on their military design, and historians such as R. Brown Cathcart King proposed that square keeps were adopted because of their military superiority over timber keeps. Most of these Norman keeps were certainly extremely physically robust, even though the characteristic pilaster buttresses added little real architectural strength to the design.<ref>King, p.67; Hulme, p.216.</ref> Many of the weaknesses inherent to their design were irrelevant during the early part of their history. The corners of square keeps were theoretically vulnerable to [[siege engines]] and galleried [[mining (military)|mining]], but before the introduction of the [[trebuchet]] at the end of the 12th century, early artillery stood little practical chance of damaging the keeps, and galleried mining was rarely practised.<ref>Hulme, pp.216, 222.</ref> Similarly, the corners of a square keep created dead space that defenders could not fire at, but missile fire in castle sieges was less important until the introduction of the [[crossbow]] in the middle of the 12th century, when [[arrowslit]]s began to be introduced.<ref>Hume, p.217.</ref>

{{Multiple image|direction=horizontal|align=right|image1=RestormelCastle.JPG|image2=Restormel Castle keep plan.jpg|width=210|caption2=|caption1=[[Restormel Castle]]'s [[shell keep]] in [[Cornwall]], England, converted to stone in the late 12th century}}
Nonetheless, many stone Norman keeps made considerable compromises to military utility.<ref>Liddiard (2005), pp.51–2.</ref> [[Norwich Castle]], for example, included elaborate [[blind arcade|blind arcading]] on the outside of the building and appears to have had an entrance route designed for public ceremony, rather than for defence.<ref>Liddiard (2005), p.51.</ref> The interior of the keep at [[Hedingham Castle|Hedingham]] could certainly have hosted impressive ceremonies and events, but contained numerous flaws from a military perspective.<ref>Liddiard (2005), p.53.</ref> Important early English and Welsh keeps such as the [[White Tower (Tower of London)|White Tower]], [[Colchester Castle|Colchester]], and [[Chepstow Castle|Chepstow]] were all built in a distinctive [[Romanesque architecture|Romanesque]] style, often reusing Roman materials and sites, and were almost certainly intended to impress and generate a political effect amongst local people.<ref>Liddiard (2005), p.34; Pettifer (2000a), p.xiii; Turner, p.27.</ref> The political value of these keep designs, and the social prestige they lent to their builders, may help explain why they continued to be built in England into the late 12th century, beyond the point when military theory would have suggested that alternative designs were adopted.<ref>Liddiard (2005), p.48; King, p.73.</ref>

The second early stone design, emerging from the 12th century onwards, was the [[shell keep]], a ''donjon annulaire'' in French, which involved replacing the wooden keep on a motte, or the palisade on a [[ringwork]], with a circular stone wall.<ref>Brown, p.42; Durand, p.29.</ref> Shell keeps were sometimes further protected by an additional low protective wall, called a [[chemise (wall)|chemise]], around their base. Buildings could then be built around the inside of the shell, producing a small inner courtyard at the centre.<ref name=Brown1962P42>Brown, p.42.</ref> The style was particularly popular in south-east England and across Normandy, although less so elsewhere.<ref>Durand, p.29, Toy (1933) cited Creighton, p.49.</ref> [[Restormel Castle]] is a classic example of this development, as is the later [[Launceston Castle]]; prominent Normandy and Low Country equivalents include [[Château de Gisors|Gisors]] and the [[Burcht van Leiden]] – these castles were amongst the most powerful fortifications of the period.<ref>Brown, p.41; Toy (1985), pp.58–9; Viollet-le-Duc, p.83.</ref> Although the circular design held military advantages over one with square corners, as noted above these really mattered from only the end of the 12th century onwards; the major reason for adopting a shell keep design, in the 12th century at least, was the circular design of the original earthworks exploited to support the keep; indeed, some designs were less than circular in order to accommodate irregular mottes, such as that found at [[Windsor Castle]].<ref name="Hulme, p.222">Hulme, p.222.</ref>