[CHAPTER VIII]
THE CONCENTRIC CASTLE, c. 1250, TO THE CASTELLATED MANSION PERIOD
The inception of the concentric idea in castellation must not be ascribed to the English builders of the second half of the thirteenth century, inasmuch as the plan is essentially oriental and appeared in the Levant before 1200. Thus Château Gaillard, built by Richard I. in 1196 upon the banks of the Seine near Les Andelys, is based essentially upon the concentric type, though it does not absolutely conform to that ideal owing to the configuration of the ground. That crusading monarch was among the first to recognise the possibilities of the Saracenic form and based this castle upon it. Upon the only side where it could be attacked it offered first an outer triangular-shaped ward, with an encircling wall, having five towers upon its enceinte. Between this and the second ward was a formidable ditch, 30 feet in depth, the wall standing upon the brink of the scarp; this second ward was of large dimensions with five towers upon its walls, which were practically built upon the edge of precipices. It was roughly hexagonal in shape and contained the inner ward, partially circular in outline and surrounded by a ditch. The walls of this ward were lofty and faced with bastions segmental in plan, thus embodying the prevailing belief that angles and corners were more vulnerable than curved surfaces. Inside this ward stood the Keep, forming the fourth successive line of defence to be overcome. The Keep or Donjon is splayed outwards at the base, a device often adopted for projecting missiles among the assailants when dropped from above, and also for greater strength. Probably the earliest examples of machicoulis are found upon this Keep. This formidable fortress fell by a combination of mining, filling up of the great ditch, battering the Keep, and escalading the inner ward, after pounding the curtain walls with perriers.
The thousands of warriors returning from the many crusades were well acquainted with the Concentric Castle, having in many cases been detained before the walls of an eastern city built upon a similar design. The difficulty and danger in attacking such a place were well known to them, and we can only ascribe the question of cost as the chief reason for the non-adoption of the idea at an earlier period.
At Constantinople the crusading hosts before the city found themselves confronted by a comparatively low fortified wall, bristling with impediments; within it, at the distance of some hundreds of feet, arose another and taller wall, while beyond that again a third wall, the highest of all, appeared. These walls extended for more than three miles upon the western side, with one hundred towers; all were embattled, and they offered a stupendous scene to the wondering eyes of the Crusaders as they vanished in grand perspective into the distance. There is no castle in England which presents more than three hundred yards of continual front. The capture of the first defence of the eastern capital by no means imperilled the integrity of the second, while the prospective losses of the assailants when confined in the narrow space between the first and second lines was appalling to contemplate. The same difficulty would occur with regard to the second and third lines of defence, and it is small wonder that the leaders paused in a projected attack upon so formidable an obstacle.
CASTLE RUSHEN, ISLE OF MAN.
The essential principles underlying the construction of a castle erected upon the concentric plan were:—