Page:Medieval Military Architecture in England (volume 1).djvu/137

 Alcdueval Military Architecture in England. 121 CHAPTER IX. THE RECTANGULAR KEEP OF A NORMAN CASTLE. IN a preceding chapter an attempt was made to describe the appearance and to give an outline of the history of those earthworks in England and Normandy upon which the Norman and Anglo-Norman barons founded their chief strong- holds, and which, therefore, are connected with the military architecture of either country. It is now proposed to describe the buildings themselves, whether placed within the ancient earthworks or altogether of original foundation, which con- stituted the fortresses of England in the eleventh and twelfth centuries, through the periods known in ecclesiastical architecture as the Norman and Transition, and which, in military architecture, include the Norman form of castle. What is known as the Norman style of architecture prevailed in England from the Conquest to the close of the reign of Stephen, — that is, from 1066 to 1 154 ; but this latter is neces- sarily an arbitrary date, since it was by degrees only that one style of architecture passed into another, and the Norman features, though found in all buildings, and especially in castles, down to the end of the reign of Henry II., or 11 89, became more and more mixed up with those of the succeeding style. The castles of the eleventh and twelfth centuries, whether in Normandy or in England, were of two distinct types, — those with the rectangular and those with the shell keep. The former type was almost always employed when the site selected was a new one, the latter where the site was old, and where there existed a " motte " or mound. There are exceptions to this ; that is to say, the rectangular keep is occasionally found on an old site, but the shell keep is never found on a new one. The distinction was mainly due to the fact that the massive heavy tower could only be safely founded upon solid ground, whereas the lighter and more widely-distributed weight of the shell keep was better suited to that which was artificial. The shell keep was the most numerous of the two ; but the tower type, being of a more solid and more durable character, has lasted longest, and is at