Very extensive additions were made by Anthony, Lord Scales, who was Lord of the Castle in 1474. The majestic gateway dates from his time; it is a fine and impressive entrance, flanked by two lofty cylindrical towers with a good example of machicolation between the towers, added late in the fifteenth century. The ruins of the apartments occupied by the royal prisoner lie to the north of the enclosure. In the reign of Queen Elizabeth an elaborate system of fortification was carried out by an Italian engineer, in view of the advent of the Spanish Armada, but was never put to use. After the Restoration many regrettable alterations and additions were made by Lord Cutts, with a view to modernising it, but some of these have been modified recently by the Crown. The picturesqueness of the ruins and their surroundings are an acknowledged feature of the island, and few visit the latter without seeing this venerable relic of the past. CHAPTER VI THE RECTANGULAR KEEP, _c._ 1100-1200 We have seen that the Shell Keep was a logical sequence in the development of a castle which had been originally erected upon the Motte and Bailey plan, and the question will naturally suggest itself as to the nature of Castles which the Normans built in the twelfth century upon a site not previously occupied. This was the Rectangular Keep with its fortified enclosure, answering approximately to the Shell Keep and the bailey. Rectangular Keeps had been prominent in French fortifications for at least thirty years before the Norman Conquest, but the introduction of the defence into England was slow and protracted. Only two examples are extant which preceded the death of William I., namely, the White Tower of London, and the Keep at Colchester. This type of castle has come to be associated with the Normans, to the practical exclusion of the much greater number of Motte and Bailey and Shell Keep fortalices which are equally connected with their occupation; probably the dignified appearance of the massive Keep, with its impressive adjuncts and surroundings, are responsible for the popular belief.