But Rickman, a member of the Society of Friends, scarcely notices castles, and they have by no means shared in the flood of light directed by Willis upon our cathedrals. Rickman’s rules, however, apply as much to one class of buildings as to the other. What has been done, and what has to be done, towards a history of the architecture of castles, though aided by contemporary records and especially by sheriffs’ accounts and Fabric rolls, has been mainly attained by attention to the internal evidence afforded by the buildings themselves and their earthworks. Even where the castle is a ruin, where the ashlar casing has been stripped off, and little left but the rubble and concrete of the interior of the walls, as at Bramber, Saffron-Walden, and Thurnham, and the disintegrating effect of the weather has had full play, it is not impossible, nor very often difficult, to detect the general age of the several parts of the building by the thickness of the walls and the character of the materials and workmanship, as well as by the outline of the works. The absence of ornament and the general removal of window-dressings and door-cases often, it is true, render the absolute date difficult to discover, but even then, the general figure of the openings, the rough contour of the arches, the position and proportion of the buttresses may be detected, and a tolerably safe conclusion formed. Perhaps, on the whole, the greatest difficulties the military antiquary has to contend with are those where, as at Norwich, Lancaster, York, Oxford, Caermarthen, or Haverfordwest, the building is converted into a gaol, or where, as at Appleby and Chilham, it is part of or attached to a modern residence. Warwick, so remarkable on many accounts, is especially so for the skilful manner in which it has been made suitable for modern habitation without materially obscuring its ancient parts, and this merit may be claimed for Tamworth, and perhaps for Raby.