Under the general name of Northmen in the ninth and tenth centuries were included all those peoples of pure Teutonic stock who inhabited the two neighboring peninsulas of Denmark and Scandinavia. In this period, and after, they played a very conspicuous part in the history of western Europe--at first as piratical invaders along the Atlantic coast, and subsequently as settlers in new lands and as conquerors and state-builders. _Northmen_ was the name by which the people of the continent generally knew them, but to the Irish they were known as _Ostmen_ or _Eastmen_, and to the English as _Danes_, while the name which they applied to themselves was _Vikings_ ["Creekmen"]. Their prolonged invasions and plunderings, which fill so large a place in the ninth and tenth century chronicles of England and France, were the result of several causes and conditions: (1) their natural love of adventure, common to all early Germanic peoples; (2) the fact that the population of their home countries had become larger than the limited resources of these northern regions would support; (3) the proximity of the sea on every side, with its fiords and inlets inviting the adventurer to embark for new shores; and (4) the discontent of the nobles, or jarls, with the growing rigor of kingly government. In consequence of these and other influences large numbers of the people became pirates, with no other occupation than the plundering of the more civilized and wealthier countries to the east, west, and south. Those from Sweden visited most commonly the coasts of Russia, those from Norway went generally to Scotland and Ireland, and those from Denmark to England and France. In fast-sailing vessels carrying sixty or seventy men, and under the leadership of "kings of the sea" who never "sought refuge under a roof, nor emptied their drinking-horns at a fireside," they darted along the shores, ascended rivers, converted islands into temporary fortresses, and from thence sallied forth in every direction to burn and pillage and carry off all the booty upon which they could lay hands. So swift and irresistible were their operations that they frequently met with not the slightest show of opposition from the terrified inhabitants.