But this was not all, such of them as were invested with civil authority now began to exercise it in their own names, and the emperors, whose power and prestige had long ago been impaired by the fratricidal strife of the children of Louis the Mild, had been so enfeebled by the recent invasions that they were unable to offer any effectual resistance. Thus were laid on the ruins of Imperialism the foundations of that feudal system which was destined later on to play so great a part in the civilisation of Europe. CHAPTER III _The House of Long Col_ Foremost among the landowners, who at this time were laying the foundations of dynasties, was Régnier au Long Col, the great ancestor of the Counts of Hainault and of the Counts of Brussels and Louvain, the man to whom all the sovereigns of Brabant, from Lambert Longbeard to Francis II., traced their descent:[2] the son of one Count Giselbert, who, in the middle of the eight hundreds, had made his fortune by carrying off a daughter of the Emperor Lothaire, he was the owner of vast estates in Hainault, in Hesbaye, in Ardennes, and lay-abbot to boot of three great monastic domains. Of the vassals and serfs who dwelt on his lands some, then, were Teutons and some were Celts, and he himself, who spoke the language of each race, was perhaps unable to say to which stock he belonged, and herein lay his strength: he was a man whose nationality was merged in the great feudal chief. [2] The reigning sovereign of Belgium, King Leopold II., is a descendant of Régnier au Long Col. (_See_ Genealogical Table VI.) Such a one could alone command the confidence of the mixed race which inhabited Lotharingia, and when presently the Emperor Arnulph set up a German king in the person of his illegitimate son, Zwentibold (895), and Régnier unfurled the standard of revolt, the discontented feudal lords to a man rallied round him.