Video
The Kalmar Union, formed in 1397, united the kingdoms of Denmark, Sweden, and Norway under a single monarch, though each kingdom remained sovereign. It was the brainchild of Queen Margaret I of Denmark, a shrewd and capable ruler who sought to counter the growing influence of the Hanseatic League, a powerful trading confederation in northern Europe. The union was officially agreed upon in Kalmar, Sweden, and brought together not only the three kingdoms but also Norway's overseas territories, such as Iceland, Greenland, and the Faroe Islands.
The roots of the union can be traced back to Queen Margaret’s lineage and political maneuvering. Margaret, the daughter of Danish King Valdemar IV, was married to King Haakon VI of Norway, who also had ties to Sweden through his father, King Magnus IV. When Margaret’s son Olaf inherited the Danish throne in 1376, and later the Norwegian throne in 1380, it seemed the groundwork for a united Scandinavian monarchy was being laid. However, Olaf’s untimely death in 1387 left Margaret without a direct heir, prompting her to adopt her great-nephew, Eric of Pomerania. Around the same time, Swedish nobles, dissatisfied with their king, sought Margaret’s aid, enabling her to defeat Sweden’s King Albert in 1389.
With Eric declared king of all three kingdoms, the coronation at Kalmar in 1397 marked the formal establishment of the union. While it was designed to provide a united front against German expansion in the Baltic region, the internal dynamics of the union were often fraught with tension. The Swedish and Danish nobility, in particular, resisted attempts by the monarchy to centralize power, and the union was periodically interrupted by revolts and conflicts, especially in Sweden.
Territorial shifts also began to test the unity. In 1468, Christian I, King of Denmark and Norway, pledged the Northern Isles of Orkney and Shetland to Scotland as a security for his daughter’s dowry, an obligation that was never fulfilled. As a result, these islands were permanently annexed by Scotland in 1472, marking a significant loss of territory for Norway.
Despite its ambitious goals, the Kalmar Union ultimately unraveled due to the deepening power struggles between the monarchs and the nobility of the three kingdoms. Sweden, especially, sought greater independence. The final blow came in 1523, when Gustav Vasa was elected King of Sweden, formally seceding from the union. Denmark’s acceptance of this secession was solidified in the Treaty of Malmö in 1524, ending the Kalmar Union and restoring Sweden’s sovereignty.