Between the end of the 8th century and around the year 1050 , the Vikings left Scandinavia on expeditions of trade, war, plunder and colonisation.
It is difficult to keep track of which Vikings went here, but a good rule-of-thumb goes as follows: Danish Vikings went to Danelaw, a series of settlements in England, and to Normandy in France. The Swedish Vikings mainly went east to Finland, Novgorod, and Kiev, while the Norwegian Vikings went to Ireland and Scotland.
In the beginning the Viking expeditions were led by local chieftains, but later kings would be in the front of the dreaded Viking attacks, as when Sweyn Forkbeard conquered England.
The Vikings' power was due mainly to the fact that they were skilled sailors and shipbuilders, and that the most important trade towns were centrally placed in Scandinavia, for example on the island of Gotland and the city of Hedeby in Jutland.