Early Scandinavian Dublin
In the year 795 Vikings (probably of Norwegian origin) raided islands off the coast of Ireland for the first time. This was the beginning of a new phase of Irish history, which saw many native communities – particularly ecclesiastical ones – relocate themselves on the continent, or further afield in places like Iceland and the Faroe Islands, to escape the pagan marauders. For about two decades the invaders confined their activities to coastal settlements; raiding parties were generally small and there is no evidence that any of them wintered in Ireland during this early phase of "hit-and-run" activity. Typically the Vikings would arrive at a settlement without warning, plunder what goods and people they could – the people were usually sold as slaves, though notable personages were often held for ransom – before retreating to their Scandinavian or British bases. This period lasted from 795 until 813, after which there occurred a hiatus of eight years.
It is now thought that these early raids were launched directly from southwest Norway, and that during the period of calm (814–820) the Norwegian Vikings were occupied in northern Britain, laying the foundations of a new kingdom referred to in Irish sources as Laithlind (later Lochlainn). Laithlind was once thought to be in Norway but it is now identified with Viking settlements in the British Isles, especially those in Scotland and the Isle of Man.
Viking Age
In Scandinavia, the Viking age is considered to have ended with the establishment of royal authority in the Scandinavian countries and the establishment of Christianity as the dominant religion. The date is usually put somewhere in the early 11th century in all three Scandinavian countries. The end of the Viking era in Norway is marked by the Battle of Stiklestad in 1030. Although Olafr Haraldsson's (later known as Olav the Holy) army lost the battle, Christianity spread, partly on the strength of rumours of miraculous signs after his death. Norwegians would no longer be called Vikings. In Sweden, the reign of king Olov Skötkonung ( 995–1020) is considered to be the transition from the Viking age to the Middle Ages, because he was the first Christian king of the Swedes, and he is associated with a growing influence of the church in what is today southwestern and central Sweden.