Viking Era: In the year 793 The AngloSaxon Chronicle refers to "the havoc of heathen men miserably destroyed God's church at Lindisfarne, through rapine and slaughter." The Viking era ended around the middle of the eleventh century
Swedish vikings: down the Russian rivers to the Black Sea and the Caspian Sea.
Norwegian vikings: the Atlantic Isles, Scotland, Ireland, Iceland, Greenland and even North America.
The Danes: along the coast of western Europe and to east England.
Peace treaty of 1323 between Sweden and Russia assigned most of Finland to Sweden. In 1362, Finns were given the right to send representatives to the election of the king in Sweden, and in the16th century this right was extended to include representation in the Swedish Diet.
In 1536 King Christian III had to pledge to the Danish noblemen that Norway was henceforth to be subservient to the Danish Crown, like any other Danish possession.
The 1848 Revolutions
The February revolutions of 1848 in many European countries have more mild parallels in Scandanavian countries. Monarchy gives way to parliamentarianism.
Lack of strong class distance (mainly due to slow industrialization and wealth accumulation) results in "Red-Green Alliance" between urban and rural workers.
Rise of "democratic socialism" (combination of strong local political power with state-financed services).
60% Income tax; 35 hour work week, 7 weeks vacation.