Denmark–Sweden Relations

The relations between Denmark and Sweden span a long history of interaction. The inhabitants of each speak related North Germanic languages, which have a degree of mutual intelligibility. Both countries formed part of the Kalmar Union between 1397 and 1523, but there exists an inherited cultural competition between Sweden and Denmark. From 1448 to 1790 the two kingdoms went to war against each other at nearly every opportunity; in more than one case a new king tried to prove his worth by waging war on the other country for little or no political reason. Eleven Dano-Swedish wars took place between 1521 and 1814.

Today, the countries are separated by the Øresund, which links the Baltic Sea and the North Sea. Denmark has an embassy in Stockholm and 2 consulates-general (in Gothenburg and Malmö). Sweden has an embassy in Copenhagen and 16 honorary consulates. Both countries are full members of the Nordic Council, of the Council of the Baltic Sea States, of the Council of Europe, and of the European Union. Around 21,000 Swedish people live in Denmark and around 42,000 Danish people live in Sweden.

Since Gustav Vasa consolidated the Swedish nation-state after the Swedish War of Liberation in 1523, Sweden and Denmark have fought 11 wars from the Northern Seven Years' War to the Napoleonic Wars. Sweden has historically won the majority of the wars, 7 of the total 11. Even though not all of these wars resulted in territorial changes and some ended in status quo, Sweden is considered victorious in many of these wars because they were triggered by Denmark. The Swedish Campaign against Norway in 1814 was Sweden’s last war with Denmark, unlike Denmark which was involved in the Schleswig wars.

Historic conflicts

Second Northern War

The Second Northern War (1655–60) was fought between Sweden and its adversaries the Polish–Lithuanian Commonwealth (1655–60), Russia ( 1656–58), Brandenburg-Prussia (1657–60), the Habsburg monarchy (1657–60) and Denmark–Norway ( 1657–58 and 1658–60). The Dutch Republic often intervened against Sweden.

In 1655, Karl X Gustav of Sweden invaded and occupied western Poland-Lithuania, the eastern half of which was already occupied by Russia. The rapid Swedish advance became known in Poland as Swedish Deluge. The Grand Duchy of Lithuania became a Swedish fief, the Polish-Lithuanian regular armies surrendered and the Polish king John II Casimir Vasa fled to the Habsburgs. Frederick William, Elector of Brandenburg and Duke of Prussia initially supported the estates in Royal Prussia, but allied with Sweden in return for receiving the Duchy of Prussia as a Swedish fief. Exploiting the hurt religious feelings of the Roman Catholic population under Protestant occupation and organizing Polish-Lithuanian military leaders in the Tyszowce Confederation, John II Casimir Vasa managed to regain ground in 1656. Russia took advantage of the Swedish setback, declared war on Sweden and pushed into Lithuania and Swedish Livonia.

Charles X Gustav then granted Frederick William I full sovereignty in the Duchy of Prussia in return for military aid, and in the Treaty of Radnot allied himself with the Transylvanian George II Rákóczi who in