156 DUFFIELD CASTLE. 



shire soon made his plans for the erection of an imposing fortress 

 at Duffield. It would not only be a costly but a tedious work, for 

 the architect, overlookers, and probably most of the masons would 

 have to be brought there from Normandy. Probably the great 

 work of the keep was finished towards the end of the Conqueror's 

 days, though its completion may possibly not have been thoroughly 

 accomplished till the next reign. 



The Norman castles, whether erected in England or in Nor- 

 mandy, were of two types ; the one had a rectangular, and the 

 other a circular or shell keep. The rule seems to have been that 

 where the site selected was a new one, the keep should be rectan- 

 gular, for so massive and heavy a tower could only with safety be 

 founded upon substantial ground or rock ; but that when it was 

 proposed to build upon a spot already used for a like purpose, the 

 shell or circular keep was adopted as the lighter style, and having 

 a more evenly distributed weight, and therefore better suited for 

 erection on a burh or artificial mound. The latter style was much 

 the commoner of the two, though, as the former was more durable, 

 many rectangular examples remain to the present time. But there 

 are exceptions to the first half of this rule, and Mr. Clark gives 

 six instances — Christchurch, Guildford, Clun, Saffron Walden, 

 Mileham, Bungay, and Bramber, in each of which rectangular 

 keeps have been erected on old sites. To these Duffield may 

 now be added ; and the reason why it was safe to do so in this 

 instance is readily explained. The English burh was only partially 

 artificial ; and on the north side the rock cropped up, and was 

 only covered to the depth of a few feet. This the Norman work- 

 men cleared off, and exposing the rock, built about one-half of 

 their great keep on the rock itself, most of the remainder being 

 founded on shale, and in one part, near the well angle, on firmly 

 " made " ground. 



"The rectangular keep," says Mr. Clark, "is of all military 

 structures the simplest in form, the grandest in outline and dimen- 

 sions, the sternest in passive strength, the most durable in its 

 design and workmanship, and in most cases, by some years the 

 earliest in date." These keeps differ in dimensions from 25 feet 



