Mediæval Military Architecture in England. 35
CHAPTER III.
OF THE CASTLES OF ENGLAND AT THE CONQUEST AND UNDER THE CONQUEROR.
IT has usually been assumed that the rapidity of William's conquest was due to the absence of strong places in England. There is, however, ground for believing that England, in this respect, was exceedingly well provided, — quite as well provided as Normandy ; and that, with the possible exception of a very few recently-constructed strong-holds, the works in the two countries were very similar in character. The older sites of the castles of the barons in Normandy are nearly all ascertained, and are for the most part distinguished by a moated mound with an appended court or courts also moated. This simple and very effective form of defence has been shown to have been in use among the Northern nations, invaders both of England and the Continent, and in the ninth and tenth centuries was as common on the banks of the Thames, the Humber, and the Severn, as on those of the Seine and the Orne. It was in the eleventh century, and chiefly during the troubles attendant upon the accession and minority of Duke William, that the Normans seem to have adopted a new and more permanent description of fortress, and the old-fashioned structure of timber began to be replaced by walls and towers in masonry, and especially by keeps of that material. Of these the best-known, because the most durable, form was the rectangular, of which not above half a dozen examples can be shown with certainty to have been constructed in Normandy before the latter part of the eleventh century, and but very few, if any, before the English conquest ; nor is there known to be in Normandy any specimen of the polygonal or circular form of keep as early as that event. De Caumont, indeed, attributes the rectangular keep of Langeais, in which brick is largely used, to the year 992 ; but there is great reason to doubt this conclusion, and Du Pin and St. Laurent are probably among the oldest of this form, and do not seem to be earlier than the reign of Duke William ; and this is true also of Arques and
