site of the second castle, there is neither trace nor tradition of any masonry at all. The building of a Norman castle required both time and money. The architects, overlookers, and probably the masons, had to be imported from Normandy, and in many cases the stone for the exterior; and as most of the existing square keeps, and very nearly all the shell keeps, are of the twelfth century, it seems probable that the Conqueror was to some extent content with such defences as he found in England; strengthened, no doubt, very materially by the superior skill and resources of his engineers. This is quite consistent with the fact that the art of castle-building did, from the building of the White Tower, undergo a great and somewhat rapid change. It is true of William, both in Normandy and in England, as Matthew Paris observes, “ad castra quoque construenda, rex antecessores suos omnes superabat”; and he, no doubt, as we are told by William of Jumieges, “tutissima castella per opportuna loca stabilavit.” Lanfranc, writing to Roger, Earl of Hereford, before his rebellion, assuring him of William’s confidence, adds, “et mandat ut quantum possumus curam habeamus de castellis suis, ne, quod Deus avertat, inimicis suis tradantur”; and in the subsequent rebellion, it was when Ralph Guader found the men of castles against him, that he left his wife and children to make terms from Norwich Castle, while he himself fled. Lanfranc’s despatch informs William, “Castrum Noruuich redditum est, et Britones qui in eo erant et terras in Anglia terra habebant, concessis eis vita et membris.” Besides the Bishop and Earl Warrene, the castle contained three hundred “loricati,” with cross-bowmen and many artificers of military machines. Also the same prelate charges Bishop Walcher, of Durham, “Castrum itaque vestrum, et hominibus, et armis, et alimentis vigilanti cura muniri facite.” Castles, no doubt, there were at William’s command, many and strong. All that is here contended for is, that whatever he may have desired, William was able to construct but few castles such as London or Durham; and that the greater number of those that remain and exhibit the Norman style of architecture belong, some to the close of the eleventh, and a greater number to the twelfth century. But if William did not actually build so many castles as is supposed, he and his followers certainly restored and occupied an immense number, upon which those who came immediately after him built structures, the ruins of which we now see.