enlist all its giant barbaric force on the side of civilization. This great work was as thoroughly done as anything that was ever done in human history, and we ought to be thankful to Caesar for it every day that we live. The frontier to be defended against barbarism was now moved away up to the Rhine, and was very much shortened; but above all, the Gauls were made to feel themselves to be Romans. Their country became one of the chief strongholds of civilization and of Christianity; and when the frightful shock of barbarism came--the most formidable blow that has ever been directed by barbaric brute force against European civilization--it was in Gaul that it was repelled and that its force was spent. At the beginning of the fifth century an enormous horde of yellow Mongolians, known as Huns, poured down into Europe with avowed intent to burn and destroy all the good work which Rome had wrought in the world; and terrible was the havoc they effected in the course of fifty years. If Attila had carried his point, it has been thought that the work of European civilization might have had to be begun over again. But near Chálons-on-the-Marne, in the year 451, in one of the most obstinate struggles of which history preserves the record, the career of the "Scourge of God" was arrested, and mainly by the prowess of Gauls and of Visigoths whom the genius of Rome had tamed. That was the last day on which barbarism was able to contend with civilization on equal terms. It was no doubt a critical day for all future history; and for its favourable issue we must largely thank the policy adopted by Caesar five centuries before. By the end of the eighth century the great power of the Franks had become enlisted in behalf of law and order, and the Roman throne was occupied by a Frank,--the ablest man who had appeared in the world since Caesar's death; and one of the worthiest achievements of Charles the Great was the conquest and conversion of pagan Germany, which threw the frontier against barbarism eastward as far as the Oder, and made it so much the easier to defend Europe. In the thirteenth century this frontier was permanently carried forward to the Vistula by the Teutonic Knights who, under commission from the emperor Frederick II., overcame the heathen Prussians and Lithuanians; and now it began to be shown how greatly the military strength of Europe had increased. In this same century Batu, the grandson of Jinghis Khan, came down into Europe with a horde of more than a million Mongols, and tried to repeat the experiment of Attila. Batu penetrated as far as Silesia, and won a great battle at Liegnitz in 1241, but in spite of his victory he had to desist from the task of conquering Europe. Since the fifth century the physical power of the civilized world had grown immensely; and the impetus of this barbaric invasion was mainly spent upon Russia, the growth of which it succeeded in retarding for more than two centuries.