The Kalmar Union, formed in 1397, was a political response to the growing influence of external powers, particularly the Hanseatic League, a powerful German trading confederation that dominated Baltic and North Sea trade. The League established trading posts in key Norwegian port cities, such as Oslo and especially Bergen, which became home to the largest German merchant colony in the country. The Hanseatic merchants dominated the import and export of goods, securing a monopoly over key resources like fish, Norway's primary export, in exchange for grain and other essential supplies. Norway, Denmark, and Sweden were struggling economically, especially after the devastation of the Black Death. The Hanseatic League capitalized on this weakness, extending its control over regional trade, which threatened the sovereignty of the Scandinavian kingdoms.
In this context, Queen Margaret I of Denmark sought to unify the three kingdoms—Denmark, Norway, and Sweden—under a single crown to present a united front against the Hanseatic League’s dominance. The union was intended to protect the region’s economic interests and strengthen political stability in Scandinavia. Margaret succeeded in bringing the three kingdoms together at the town of Kalmar in 1397, creating what became known as the Kalmar Union.
For Norway, already weakened by population loss and economic decline after the Black Death, the union marked the start of a long period of political subordination. While the union was designed to respect the sovereignty of each kingdom, Denmark emerged as the dominant power. Norway's political influence faded, and much of its administration and trade came under Danish control.
Although the Kalmar Union aimed to protect Scandinavian interests against the Hanseatic League, it led to centuries of Danish dominance over Norway, which lasted until the union’s dissolution in 1523 when Sweden left. Norway, however, remained united with Denmark in a dual monarchy until 1814. The union, although initially a defensive strategy, resulted in Norway losing much of its political autonomy and influence.