Historians and writers, from the Viking Age onward, have suggested many different reasons why, between the years 800-1100, there was this sudden surge of activity on the part of the Scandinavian people:
• Monastic writers thought it was God’s punishment.
• European clerics, such as Adam of Bremen and Dudo of St-Quentin, attributed it to over-population and land shortage in Scandinavia. However, there is no real evidence for this, and in some places, such as Rogaland in southwest Norway and the Baltic island of Oland, archaeological evidence suggests that the population seems to have been larger in the sixth century.
• The development of the classic Viking ship has been seen as a key to the Viking Age, and certainly without it the Viking Age would not have been possible.
• Icelanders, such as Ari Thorgilsson and Snorri Sturluson, thought the Vikings left Scandinavia to avoid the growing power of kings. Certainly during the Viking Age, the kings of Denmark and Norway had much more power and control over their countries than had previously been the case.
• There also appears to have been a trading boom in Europe— improved ships made it possible to travel and exchange goods farther afield than before.
The account that the Norwegian trader, Ohthere, gave to King Alfred of England also provides an insight into some of the reasons why Scandinavians traveled in the Viking Age. He mentions trading as one of the reasons for his journey, but also curiosity—he wanted to explore the regions of north Norway because he did not know what type of country and, perhaps more importantly, what resources he might find there. He discovered the existence of a number of Sami tribes and was able to impose tribute on them, and so to exercise a sort of economic power. Certainly the desire to acquire wealth—either moveable wealth in the form of loot or fixed wealth in the form of land or even wealth through employment—was an extremely important motive that helped to trigger the journeys of the Viking Age and that underlies many of the expeditions. The desire to gain political power was also important and was an extension of this economic motive: political power meant that you could impose taxes and tribute and control trade. However, there can be no one single explanation of the Viking Age: motives varied over the three hundred years for which it lasted and across the vast distances of Scandinavia. The only real agreement today is that many different factors played a part in triggering this wave of outward activity.