William established a strong government. Had Harold been unopposed from without, he would have had rivals from within the nation. The opposition of his own brother Tostig was but a prelude of what the general result of his reign would have been. Ambitious men, such as Edwin and Morcar, the Earls of Mercia and Northumbria, would on the least provocation have espoused the cause of Edgar Atheling, and by rendering the land a scene of internal discord, have made it an easy prey to new bands of adventurers from Denmark, Norway, Flanders, and France. William, by the vigour, and even harshness of his rule, quelled internal dissension, and bid defiance to foreign rivalry. The Norman invasion hastened and perfected the establishment of the feudal system in England. This system had one great defect, which renders it unfit for the present condition of England--it altogether overlooked the claims of the lower classes, who always form the great bulk of the population; still, it produced most beneficial results in the eleventh and twelfth centuries. It brought all the great barons of the empire into subjection to the sovereign, and by defining the corresponding duties of the mesne lords and inferior tenants, knit the whole kingdom into one. By this unity the realm was prepared to put down intestine broils, and to resist foreign aggression. A way too was prepared for the elevation of the lower classes. The system had but to be extended in order to define the duties, and to confer corresponding privileges, upon every member of the community.