The Vikings, active in the east, travelled as far as the Black and Caspian Seas, where they developed trading links with the Byzantine Empire and the Arab dominions. At the same time, Christianity first reached Sweden with the mission of Ansgar, who visited the country from the Carolingian Empire in the ninth century.

Sweden's expansion in the east continued during the twelfth and thirteenth centuries through the incorporation of Finland into the Swedish kingdom after several crusades.

After its defeat in the Great Northern War (1700-21) against the combined forces of Denmark, Poland and Russia, Sweden lost most of its provinces on the other side of the Baltic and was reduced to largely the same frontiers as present day Sweden and Finland. During the Napoleonic Wars, Finland was finally surrendered to Russia and Sweden's last possessions in northern Germany were also lost. As compensation for these losses, the French marshal Jean Baptiste Bernadotte, who had been elected heir to the Swedish throne in 1810, succeeded in obtaining Norway, which was forced into a union with Sweden in 1814. This union was peacefully dissolved in 1905 after many internal disputes.

Nineteenth-century Sweden was also marked by the emergence of strong popular movements like the free churches, the temperance and feminist movements and, above all, the labour movement. The latter, which grew in pace with industrialisation in the second half of the nineteenth century, was reformative in outlook after the turn of the century and the first representatives of social democracy entered the government as early as 1917. Universal suffrage was introduced for men in 1909 and for women in 1921, and this latter date also marked the breakthrough for the principle of parliamentary government. Plans for a welfare society were laid during the 1930s after the Social Democrats had become the governing party, and it proved possible to put these plans into effect in all essentials after the Second World War.

Sweden today is characterised by a high average standard of living and a well-developed system of social security, but at the same time by a decline in certain sections of trade and industry, which has led to a substantial measure of economic restriction. The formulation of Swedish foreign and security policy is changing as Europe changes. The concept of "neutrality" will no longer be adequate as an overall description of this policy. At the same time, Sweden is not a member of any military alliance and still bears responsibility for independently defending and protecting its extensive territory. Greater importance is being attached to a European identity in foreign policy, manifested not only by the application for membership of the EU but also by efforts to develop contacts with the emerging new democracies in Central and Eastern Europe. Sweden is also an active participant in international co-operation. Strong support for the United Nations is one cornerstone of its foreign policy. Other basic elements are the promotion of human rights, international disarmament and a better environment.