2. Charles’s greatest work, as has been once or twice hinted in the course of the preceding narrative, was his extension and consolidation of the Frankish kingdom. One cannot see that he did much for what we now call France, but his work east of the Rhine was splendidly successful. Converting the Saxons,--a triumph of civilization, however barbarous were the methods employed,--subduing the rebellious Bavarians, keeping the Danes and the Sclavonic tribes on his eastern border in check, and utterly crushing the Avars, he gave the Teutonic race that position of supremacy in Central Europe which, whatever may have been the ebb and flow of Teutonism in later centuries, it has never been forced to surrender, and which, with all its faults, has been a blessing to Europe. 3. As to the assumption of the imperial title, it is much more difficult to speak with confidence. We have seen reason to think that Charles himself was only half persuaded of its expediency. It was a noble idea, this revival of the old world-wide empire and its conversion into a _Civitas Dei_, the realized dream of St. Augustine. But none knew better than the monarch himself how far his empire came short of these grand prophetic visions; and profounder scholars than Alcuin could have told him how little it had really in common with the state which was ruled by Augustus or by Trajan. That empire had sprung out of a democratic republic, and retained for centuries something of that resistless energy which the consciousness of self-government gives to a brave and patient people. Charles’s empire was cradled, not in the city but in the forest; its essential principle was the loyalty of henchmen to their chief; it was already permeated by the spirit of feudalism, and between feudalism and any true reproduction of the _Imperium Romanum_ there could be no abiding union. I need not here allude to the divergence in language, customs and modes of thought between the various nationalities which composed the emperor’s dominions. The mutual antagonism of nations and languages was not so strong in the Middle Ages as it has been in our own day, and possibly a succession of able rulers might have kept the two peoples, who in their utterly different languages swore in 842 the great oath of Strasburg,[76] still one. But the spirit of feudalism was more fatal to the unity of the empire than these differences of race and language. The mediæval emperor was perpetually finding himself overtopped by one or other of his nominal vassals, and history has few more pitiable spectacles than some that were presented by the rulers of the Holy Roman Empire--men bearing the great names of Cæsar and Augustus--tossed helplessly to and fro on the waves of European politics, the laughing-stock of their own barons and marquises, and often unable to provide for the ordinary expenses of their households.