Olaf was a descendant of the race of Harold Haarfager, "Fair-haired Harold," the warrior who had united the kingdom of Norway, and made himself its chief king at the close of the ninth century. But Olaf came of a branch of the royal house that civil war had reduced to desperate straits. He was born when his mother, Astrid, was a fugitive in a lonely island of the Baltic. As a boy he was sold into slavery in Russia. There, one day, in the marketplace of an Esthonian town, he was recognized by a relative, Sigurd, the brother of Astrid, and was freed from bondage and trained to arms as a page at the Court of the Norse adventurers who ruled the land. The "Saga" tells how Olaf, the son of Tryggva, grew to be tall of stature, and strong of limb, and skilled in every art of land and sea, of peace and war. None swifter than he on the snow-shoes in winter, no bolder swimmer when the summer had cleared the ice from the waters. He could throw darts with both hands, he could toss up two swords, catching them like a juggler, and keeping one always in the air. He could climb rocks and peaks like a mountain goat. He could row and sail, and had been known to display his daring skill as an athlete by running along the moving oars outside the ship. He could ride a horse, and fight, mounted or on foot, with axe or sword, with spear or bow. In early manhood he came back to Norway to avenge the death of his father Tryggva, and then took to sea-roving, for piracy was still the Norseman's trade. He raided the shores of the Continent from Friesland to Northern France, but most of his piratical voyages were to the shores of our own islands, and many a seaboard town in England, Wales, Scotland, and Ireland saw Olaf's plundering squadron of swift ships. Five was the number of them with which he visited the Orkneys. The Viking warships were small vessels. The ship dug out of the great grave mound at Sandefjord, in Norway, and now shown at Christiania, is seventy-seven feet long, with a beam of seventeen amidships, and a depth of just under six feet. Her draught of water would be only four feet, and she would lie very low in the water, but her lines are those of a good sea boat. She had one mast, forty feet high, to carry a crossyard and a square sail, and she had thirty-two oars, sixteen on each side. It says something for the seamanship of the Northmen that it was with ships like this they sailed the Atlantic waves off the west coast of Ireland, and made their way by the North Sea and the verge of the Arctic to the Faroes, Iceland, Greenland, and the mysterious "Vineland."[4]