In the eleventh century the northern and central parts of the Scandinavian peninsula were occupied by a people who are often called Lapps but who called themselves Saami. Contemporaries distinguished four main groups of Scandinavians: Danes, Götar, Svear and Norwegians or Northmen. By the year 1200 most of the territory occupied by these Scandinavians had been incorporated in the three medieval kingdoms: Norwegian kingdom, Danish kingdom, and Swedish kingdom. The Danish kingdom was the first to be firmly established. The Swedish kingdom was formed by the unification of the Götar and the Svear. The earliest Scandinavian historians, writing in the twelfth and thirteenth centuries, believed that the Danish kingdom had existed since time immemorial and that the kingdoms of Norway and Sweden were relatively recent creations formed by the unification of many small kingdoms. The founder of the medieval Norwegian dynasty was Harald Hardrada. The earliest of the provincial laws, for the west Norwegian province, survives in a twelfth-century version.

During the eleventh century, Christianity was accepted as the public religion in most of Scandinavia. The conversion of the Finns, a process that was not completed until the high Middle Ages, was closely related to their incorporation in the Swedish kingdom. The missionaries working in Scandinavia from the ninth century were in large part Benedictine monks. The first Nordic religious houses were a couple of Benedictine monasteries established in Denmark towards the end of the eleventh century. The ecclesiastical demands for immunities and rights of various kinds culminated in the second half of the thirteenth century. To a large extent these demands were met, but there were soon counter-reactions because the secular aristocracy and the monarchy felt threatened by the economic resources and autonomy of the Church. The doctrines and moral code of the Church influenced people's lives throughout the Middle Ages. The chapter also discusses the extent to which the teaching of the Church managed to change Scandinavian mentality.