FIRST PERIOD 62 INTRODUCTORY brochs is unknown, but they are supposed to be the work of the native Celts. They have probably some affinity with the early dry-stone churches and cells of Ireland. These brochs may perhaps be the northern form of the wooden burghs, which the Norsemen in France and England built on the top of their " mottes ; " but in Scotland, where stone abounded, they were constructed in stone instead of timber. If so, and if the brochs represent the usual form of the early castles of Scotland, it might be supposed that they would have a material influence on the subsequent forms of construction. We have, however, not been able to trace any connection between them and the arrangements of the earliest castles built with stone and lime. But in the towers of a later date, as we shall see, the tendency to hollow out the walls with innumerable small apartments is carried to an extreme length, which may possibly be a tra- dition from these ancient brochs. It is probable that the building of castles with stone and lime was introduced into Scotland, as into Eng- land, by the Normans. During the eleventh and twelfth centuries the pressure of the Normans in England drove the Saxon nobility northwards, and these were followed by numerous Normans, who were welcomed at the Scottish Court, and obtained large domains in the country. It was no doubt the policy of these adventurers to establish themselves in the same position as the native chiefs who had to make way for them. They would thus naturally take possession of such strongholds as they found, which probably consisted of an enclosing wall on some naturally strong site, or of an area surrounded with a ditch and palisaded mound, with a natural or artificial height within on which the dwelling of the chief, usually built in wood, would be placed. This course was often adopted by the Normans in England, and it may be remarked that their position in England under the Confessor is very similar to their position in Scotland in the twelfth century. Many Normans, encouraged by the Confessor, had settled in England, but it was not till after the Conquest that the Normans took root in the country and began to build castles in their own style. So likewise in Scotland the Norman nobles do not appear to have built castles in their own style for at least a century after their first arrival. But whatever the early castles of the Norman Period in Scotland were, they have all disappeared. They have probably for the most part been remodelled into the castles of a later period, or have been demolished in the frequent sieges of those stormy times. But although no original Norman castles are to be found in Scotland, the rectangular keeps of the Normans have formed the model after which most of our Scotch castles have been constructed. During the three or four centuries succeeding the War of Independence,, there is a constant succession of castles built upon the Norman model, which present us with a faithful likeness of their originals. This was also the case in the north of England : wherever and when-
