as far as Constantinople, two main routes lay open to the masters of the northern seas. One led west to the Orkneys, the Shetlands, and the coast of Scotland, and then either south to the shores of Ireland, or further west to Iceland, Greenland, and America. The other led through the North Sea to England, the Low Countries, and the coast of Gaul. Both were used, and used freely, by the Vikings, and in both directions they accomplished enduring results:—Iceland and the kingdoms of the isles in the north, the beginnings of town life and commerce in Ireland, the Danelaw in England, and the duchy of Normandy.
When the great northern invasions began at the close of the eighth century, Charles the Great ruled all the Christian lands of the western Continent. By fire and sword he converted the heathen Saxons of the north to Christianity and civilization and advanced his frontier to the Danish border, so that the pious monk of St. Gall laments that he did not conquer the Danes also—"be it that Divine Providence was not then on our side, or that our sins rose up against us." And this same gossiping chronicler—not the best of authorities it is true—has left us a striking picture of Charlemagne's first experience with the Scandinavian invaders:—
