Chance has preserved for us in a Sleswick peat-bog one of the war-keels of these early pirates.

The boat is flat-bottomed, seventy feet long and eight or nine feet wide, its sides of oak boards fastened with bark ropes and iron bolts.

Fifty oars drove it over the waves with a freight of warriors whose arms, axes, swords, lances, and knives, were found heaped together in its hold.

Like the galleys of the Middle Ages such boats could only creep cautiously along from harbour to harbour in rough weather; but in smooth water their swiftness fitted them admirably for the piracy by which the men of these tribes were already making themselves dreaded.

Its flat bottom enabled them to beach the vessel on any fitting coast; and a step on shore at once transformed the boatmen into a war-band.