Yet more widespread in destruction, more important in result than the raids of either Saracens or Magyars, were those of the Scandinavians or Northmen. These, the latest, and perhaps therefore the finest, flower of the Teutonic stock, are closer to us and hence better known than the early Goths or Franks. Shut off in their cold northern peninsulas and islands, they had grown more slowly, it may be, than their southern brethren. Now they burst suddenly on the world with spectacular dramatic effect, wild, fierce, and splendid conquerors, as keen of intellect and quick of wit as they were strong of arm and daring of adventure. We see them first as sea-robbers, pirates, venturing even in Charlemagne's time to plunder the German and French coasts. One tribe of them, the Danes, had already been harrying England and Ireland. Only Alfred,[5] by heroic exertions, saved a fragment of his kingdom from them. Later, under Canute,[6] they become its kings. The Northmen penetrate Russia and appear as rulers of the strange Slavic tribes there; they settle in Iceland, Greenland, and even distant and unknown America.[7] [Footnote 5: See _Career of Alfred the Great_.] [Footnote 6: See _Canute Becomes King of England_.] [Footnote 7: _Leif Ericson Discovers America_.] Meanwhile, after Charlemagne's death they become a main factor in the downfall of his empire. Year after year their little ships plunder the undefended French coast, until it is abandoned to them and becomes a desert. They build winter camps at the river mouths, so that in the spring they need lose less time and can hurry inland after their retreating prey. Sudden in attack, strong in defence, they venture hundreds of miles up the winding waterways. Paris is twice attacked by them and must fight for life. They penetrate so far up the Loire as to burn Orleans. It was under stress of all these assaults that the Franks, grown too feeble to defend themselves as Charlemagne would have done, by marching out and pursuing the invaders to their own homes, developed instead a system of defence which made the Middle Ages what they were. All central authority seemed lost; each little community was left to defend itself as best it might. So the local chieftain built himself a rude fortress, which in time became a towered castle; and thither the people fled in time of danger. Each man looked up to and swore faith to this, his own chief, his immediate protector, and took little thought of a distant and feeble king or emperor. Occasionally, of course, a stronger lord or king bestirred himself, and demanded homage of these various petty chieftains. They gave him such service as they wished or as they must. This was the "feudal system."[8] [Footnote 8: See _Feudalism: Its Frankish Birth and English Development_.]