The sea-rovers did not confine their voyages to settled lands. Bold ocean wanderers, fearless of man on shore and tempest on the waves, they visited all the islands of the north and dared the perils of the unknown sea. They rounded the North Cape and made their way into the White Sea as early as 750. The Faroe, the Orkney and the Shetland Islands were often visited by them after 825, and in 874 they discovered Iceland, which had been reached and settled by Irishmen or Scots about 800. The Norsemen found here only some Irish hermits and monks, and these, disturbed in their peaceful retreat by the turbulent newcomers, made their way back to Ireland and left the Norsemen lords of the land. From Iceland the rovers reached Greenland, which was settled in 986, and about the year 1000 they discovered North America, at a place they named Vinland. Such is, briefly told, the story of the early Norse wanderers. They had a later tale, of which we have told part in their conquest of Ireland. Though at first they came with a few ships, and were content to attack a town or a monastery, they soon grew more daring and their forces larger. A number of them would now fortify themselves on some coast elevation and make it a centre for plundering raids into the surrounding country. At a later date many of them ceased to pose as pirates and took the role of invaders and conquerors, storming and taking cities and founding governments in the invaded land. Such was the work of Thorgisl and Olaf in Ireland and of Rollo in Normandy. England was a frequent field of invasion after 833, which continued until 851, when King Ethelwulf defeated them with great slaughter. Fifteen years later they came again, these new invaders being almost all Danes. During all his reign Alfred the Great fought with them, but in spite of his efforts they gained a footing in the island, becoming its masters in the north and east. A century later, in 1016, Canute, the king of Denmark, completed the conquest and became king of all England. This is not the whole story of the sea-kings, whose daring voyages and raids made up much of the history of those centuries. One of the most important events in viking history took place in 862, when three brother chiefs, probably from Sweden, who had won fame in the Baltic Sea, were invited by the Russian tribes south of Lake Ladoga to come and rule over them. They did so, making Novgorod their capital. From this grew the empire of Russia, which was ruled over by the descendants of Rurik, the principal of these chiefs, until 1598.