We are told by men of science that all the ventures of mariners on the sea, all that counter-marching of tribes and races that confounds old history with its dust and rumour, sprang from nothing more abstruse than the laws of supply and demand, and a certain natural instinct for cheap rations. To any one thinking deeply, this will seem a dull and pitiful explanation. The tribes that came swarming out of the North and East, if they were indeed pressed onward from behind by others, were drawn at the same time by the magnetic influence of the South and West. The fame of other lands had reached them; the name of the eternal city rang in their ears; they were not colonists, but pilgrims; they travelled towards wine and gold and sunshine, but their hearts were set on something higher. That divine unrest, that old stinging trouble of humanity that makes all high achievements and all miserable failures, the same that spread wings with Icarus, the same that sent Columbus into the desolate Atlantic, inspired and supported these barbarians on their perilous march. There is one legend which profoundly represents their spirit, of how a flying party of these wanderers encountered a very old man shod with iron. The old man asked them whither they were going; and they answered with one voice: "To the Eternal City!" He looked upon them gravely. "I have sought it," he said, "over the most part of the world. Three such pairs as I now carry on my feet have I worn out upon this pilgrimage, and now the fourth is growing slender underneath my steps. And all this while I have not found the city." And he turned and went his own way alone, leaving them astonished.