David, as Burton remarks, had lived for sixteen years as an affluent Anglo-Norman noble, before his accession to the Scottish crown, being Earl of Huntingdon in right of his wife, the daughter of Simon de Senlis, and granddaughter, through her mother, of Earl Waltheof. David's tastes and sympathies were Norman, but it was not taste alone which impelled him to build up in Scotland a monarchy of the Anglo-Norman feudal type. He had a distinct policy to accomplish; he wished to do for Scotland what Edward I. sought to do for the whole island, to unite its various nationalities under one government, and he saw that men of the Anglo-Norman type would be the best instruments of this policy.[1001] It mattered little to him from what nation he chose his followers, if they were men who accepted his ideas. Norman, English, Flemish, or Norse adventurers were all received at his court, and endowed with lands in Scotland, if they were men suitable for working the system which he knew to be the only one available for the accomplishment of his policy. And that system was the feudal system. He saw that feudalism meant a higher state of civilisation than the tribalism of Keltic Scotland, and that only by the complete organisation of feudalism could he carry out the unification of Scotland, and the subjugation of the wild Keltic tribes of the north and west.[1002] The policy was successful, though it was not completely carried out until Alexander III. purchased the kingdom of the Isles from the King of Norway in 1266. The sons of David, Malcolm IV., and William the Lion were strong men who doughtily continued the subjugation of the Keltic parts of Scotland, and distributed the lands of the conquered among their Norman or Normanised followers. The struggle was a severe one; again and again did the North rebel against the yoke of the House of Malcolm. In Moray the Keltic inhabitants were actually driven out by Malcolm IV., and the country colonised by Normans or Flemings.[1003] The same Malcolm led no less than three expeditions against Galloway, where in spite of extensive Norse settlements on the coast, the mass of the inhabitants appear to have been Keltic.[1004]