Keep

The first keeps were made of timber and formed a key part of the motte-and-bailey castles that emerged in Normandy and Anjou during the 10th century; the design spread to England, Portugal,[2] south Italy and Sicily.

The Anglo-Normans and French rulers began to build stone keeps during the 10th and 11th centuries, including Norman keeps, with a square or rectangular design, and circular shell keeps.

In Spain, keeps were increasingly incorporated into both Christian and Islamic castles, although in Germany tall fighting towers called bergfriede were preferred to keeps in the western fashion.

Meanwhile, tower keeps in England became popular amongst the most wealthy nobles: these large keeps, each uniquely designed, formed part of the grandest castles built during the period.

[6] The issue was complicated by the building of fortified Renaissance towers in Italy called tenazza that were used as defences of last resort and were also named after the Italian for to hold or to keep.

[12] William the Conqueror then introduced this form of castle into England when he invaded in 1066, and the design spread through south Wales as the Normans expanded up the valleys during the subsequent decades.

[13] In a motte-and-bailey design, a castle would include a mound called a motte, usually artificially constructed by piling up turf and soil, and a bailey, a lower walled enclosure.

[15] One contemporary account of these keeps comes from Jean de Colmieu around 1130, who described how the nobles of the Calais region would build "a mound of earth as high as they can and dig a ditch about it as wide and deep as possible.

The entrance to the fortress is by means of a bridge, which, rising from the outer side of the moat and supported on posts as it ascends, reches to the top of the mound.

"[17] At Durham Castle, contemporaries described how the keep arose from the "tumulus of rising earth" with a keep reaching "into thin air, strong within and without", a "stalwart house...glittering with beauty in every part".

[36] Norman keeps had four sides, with the corners reinforced by pilaster buttresses; 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.

[45] Norwich Castle, for example, included elaborate blind arcading on the outside of the building and appears to have had an entrance route designed for public ceremony, rather than for defence.

[47] Important early English and Welsh keeps such as the White Tower, Colchester, and Chepstow were all built in a distinctive Romanesque style, often reusing Roman materials and sites, and were almost certainly intended to impress and generate a political effect amongst local people.

One traditional explanation for these developments emphasises the military utility of the new approaches, arguing, for example, that the curved surfaces of the new keeps helped to deflect attacks, or that they drew on lessons learnt during the Crusades from Islamic practices in the Levant.

Within the Capetian territories, early experimentation in new keep designs began at Houdan in 1120, where a circular keep was built with four round turrets; internally, however, the structure remained conventionally square.

[62] As historian Philippe Durand suggests, these keeps provided military security and were a physical representation of the renouveau capétien, or Capetian renewal.

[70] Gaillard was designed to reaffirm Angevin authority in a fiercely disputed conflict zone and the keep, although militarily impressive, contained only an anteroom and a royal audience chamber, and was built on soft chalk and without an internal well, both serious defects from a defensive perspective.

[75] These designs included stone versions of the traditional Bergfriede, which still remained distinct from the domestic keeps used in more western parts of Europe, with the occasional notable exception, such as the large, residential Bergfried at Eltville Castle.

But French designs in the late 12th century took the layout of a contemporary unfortified manor house, whose rooms faced around a central, rectangular courtyard, and built a wall around them to form a castle.

[78] The result, illustrated initially at Yonne, and later at Château de Farcheville, was a characteristic quadrangular layout with four large, circular corner towers.

[nb 5] This shift reflected political and social pressures, such as the desire of the wealthiest lords to have privacy from their growing households of retainers, as well as the various architectural ideas being exchanged across the region, despite the ongoing Hundred Years War between France and England.

[83] The Vincennes keep was copied elsewhere across France, particularly as the French kings reconquered territories from the English, encouraging a style that emphasised very tall keeps with prominent machicolations.

The French model spread into Iberia in the second half of the century, where the most powerful nobles in Castile built a number of similar tall keeps, such as that at Peñafiel, taking advantage of the weakness of the Castilian Crown during the period.

[87] Smaller versions of these keeps were subsequently built by many aspiring new aristocracy in Spain, including many converted Jews, keen to improve their social prestige and position in society.

They were probably partially inspired by designs in France, but they also reflected the improvements in the security along the Scottish border during the period, and the regional rise of major noble families such as the Percies and the Nevilles, whose wealth encouraged a surge in castle building at the end of the 14th century.

[95] In Scotland, the construction of Holyrood Great Tower between 1528 and 1532 drew on this English tradition, but incorporated additional French influences to produce a highly secure but comfortable keep, guarded by a gun park.

[98][nb 6] It was originally argued that Irish tower houses were based on the Scottish design, but the pattern of development of such castles in Ireland does not support this hypothesis.

[107] Keeps were singled out for particular attention in this process because of their continuing political and cultural importance, and the prestige they lent their former royalist owners – at Kenilworth, for example, only the keep was slighted, and at Raglan, the keep was the main focus of parliamentary activity.

[112] Where there was an existing castle on a site, another response across 19th-century Europe was to attempt to improve the buildings, bringing their often chaotic historic features into line with a more integrated architectural aesthetic, in a style often termed Gothic Revivalism.

[116] In the 21st century in England, most keeps are in ruins and form part of the tourism and heritage industries, rather than being used as functioning buildings – the keep of Windsor Castle being a rare exception.