Within a few years of the Conquest, the Normans erected in various parts of England important edifices, both military and ecclesiastical, in truly astonishing numbers: and of these, in addition to the cathedrals and the greater churches, there still exist many noble castellated relics, some of them in a proximate degree retaining the leading features of their original arrangement, form, and appearance. At the same time, even in the case of the most perfect of the existing castles, many changes of grave importance have been introduced as century has succeeded to century; so that now, whenever any one early castle is examined with a view to trace out and to determine both what it was at the first, and in what order and with what motives certain palpable alterations and innovations have followed one another, it always is highly satisfactory to feel that an unquestionable general uniformity of plan and arrangement in all the early castles enables each one of them that is still in being, in some degree at any rate, to illustrate and explain every other. As a matter of course, whenever the architectural features in any old castle are original, the great art of the architect is able, unaided and beyond all controversy, to tell its own historical tale: but, genuine original architectural features are not always available to give their conclusive evidence; and, but too frequently, without some external aid, it is not possible to follow the career of the two terrible adversaries of early edifices (and particularly those of the noblest rank), demolition and restoration—demolition, either wilful or the result of accident and chance; and restoration, which always is wilful, though happily not always equally destructive.