Kalmar Union

The Kalmar Union was a unique political arrangement in Scandinavia. It was a personal union that joined three kingdoms under one single monarch. These kingdoms were Denmark, Norway, and Sweden. At the time, Sweden also included much of present-day Finland. The union also controlled Norway's maritime colonies. These included Iceland, Greenland, the Faroe Islands, and the Northern Isles of Orkney and Shetland.

Legally, the three kingdoms remained separate sovereign states. This means they each kept their own identity and laws. However, they shared a common monarch who directed their foreign and domestic policies. The union was designed to make the Scandinavian lands stronger together. One major goal was to counter the Hanseatic League. This was a powerful northern German trade league. The League controlled much of the trade in the Baltic and North Seas. By uniting, the Scandinavian leaders hoped to block German expansion into the Baltic region.

Queen Margaret I of Denmark was the primary architect of the union. She was a highly influential leader with deep royal connections. Margaret was the daughter of King Valdemar IV of Denmark. She married King Haakon VI, who ruled both Norway and Sweden. After her son Olaf II inherited the Danish and Norwegian crowns, Margaret became regent. When Olaf died in 1387, she adopted her great-nephew, Eric of Pomerania. Margaret helped Eric become the King of Norway in 1389. In 1396, he was elected King of Denmark and Sweden. His coronation took place in Kalmar on June 17, 1397.

The union faced constant internal conflict between different groups. The monarchs often wanted a strong, unified state. In contrast, the Swedish and Danish nobility often resisted this central power. These diverging interests caused several interruptions to the union. In the 1430s, conflicts began to hamper the union's stability. One major event was the Engelbrekt rebellion in 1434. This rebellion was partly caused by King Erik's foreign policy. His conflicts with the Hanseatic League required higher taxes. These taxes also made it harder to export Swedish iron.

Leadership struggles continued throughout the 15th century. After the death of Christopher of Bavaria in 1448, the kingdoms were not always united. Two leaders, Karl Knutsson Bonde and Christian of Oldenburg, fought for control. Karl ruled Sweden and Norway at different times. Christian ruled Denmark, Norway, and parts of Sweden. In 1471, Sten Sture the Elder defeated Christian at the Battle of Brunkeberg. Following this, Sweden was often ruled by "protectors of the realm" called riksföreståndare. These leaders, including Sten Sture the Younger, tried to maintain Swedish control while Danish kings attempted to assert their authority.

The union entered a violent phase in the early 1500s. In 1520, the Danish King Christian II invaded Sweden with a large army. This led to the Stockholm Bloodbath, where many supporters of Sten Sture the Younger were executed. This event triggered the Swedish War of Liberation. A man named Gustav Vasa organized a rebellion in Dalarna. He formed an alliance with the city of Lübeck to conquer most of Sweden. On June 6, 1523, Gustav Vasa was elected King of Sweden. His victory and his entry into Stockholm 11 days later marked the final secession of Sweden from the union.

The end of the union changed the map of Europe. In 1524, the Danish king formally gave up his claim to Sweden through the Treaty of Malmö. Some structures of the union lasted a bit longer. In 1536 or 1537, Norway became a Danish province. While Norway kept its own laws, its central institutions were dissolved. This created a Denmark–Norway union that lasted nearly 300 years until 1814. Historians note that the union was always unstable. Large territories and difficult geography made it hard to control. The varied effects of foreign policy also caused tension between the three kingdoms.