The Middle Ages were a time of intermittent warfare in Scandinavia, with recurring power struggles and ever-shifting borders. Yet in the late 14th century, a remarkable woman, Queen Margrete I, managed to unite the three kingdoms of Denmark, Sweden, and Norway in what became known as the Kalmar Union. The decades leading up to this union, and the century and a quarter that followed its establishment, witnessed some of the most dramatic events in Scandinavian history.

Historical Background: Chaos in Denmark

In the 1330s, Denmark was without a king and under the control of various provincial counts following the calamitous reign of Christoffer II, which had seen the country descend into turmoil through peasant revolts and conflicts with the Church and the powerful Hanseatic League (Hansa), an alliance of mercantile cities in northern Germany, led by Lübeck, that dominated trade in northern Europe for more than three centuries.

At this time, Sweden and Norway were ruled by the young Magnus Eriksson, who had become king of both kingdoms in 1319 at the age of three as the grandson of both King Håkon V Magnusson of Norway (ruled 1299-1319) and King Magnus Ladulås of Sweden (ruled 1275-1290). When a delegation from Skåne (the southernmost part of present-day Sweden) came to Magnus in 1332 stating that they would rather be ruled by Sweden than by a Danish count, Magnus saw an opportunity to expand his kingdom and managed to negotiate the purchase of the Skåne territories for a large sum of silver.

Denmark Regroups, While Trouble Arises in Sweden

In 1340, Valdemar Atterdag, the youngest son of Christoffer II, was chosen as King of Denmark and quickly began rebuilding the splintered kingdom. He invaded Skåne and reclaimed the province, along with neighboring Blekinge and Halland, from Sweden in 1360. The following year he conquered the islands of Öland and Gotland off Sweden’s east coast.

Meanwhile in Sweden, financial issues – including crippling debts from the purchase of Skåne – led to a power struggle between King Magnus and the nobility, including Magnus’s own sons Erik and Håkon. Håkon already ruled Norway, having replaced his father as king due to discontent with Magnus’s attempts to rule Norway from Sweden. The intention was that Magnus’s elder son, Erik, would eventually inherit the Swedish crown, but following Erik’s sudden death in 1359, Håkon and Magnus reached an agreement by which they would jointly rule Sweden.

In 1363, Håkon married Valdemar Atterdag’s daughter, Margrete, likely motivated in part by the hope of regaining Skåne. However, the marriage caused new conflicts with the Swedish nobility, resulting in outright rebellion against Håkon and Magnus. Several leading nobles who had been driven into exile threw their support behind a German prince, Albrekt of Mecklenburg, a son of Magnus’s sister Eufemia. Marching virtually unopposed through Sweden, Albrekt made a triumphant entry into Stockholm and was crowned king in early 1364.

Magnus and Håkon made an attempt to regain power in Sweden, but were unsuccessful. Defeated in battle in 1365, Håkon was driven back to Norway, with only a few western Swedish provinces remaining under his control, while Magnus was imprisoned for six years, until his son managed to gain his release in 1371.

Margrete Unites Scandinavia

At the time of her marriage to King Håkon, Margrete was only 10 years old, 12 or 13 years younger than her husband. She remained in Denmark for another three years before being brought to Norway. In 1370, when Margrete was 17, she gave birth to her only child, Olav (also spelled Oluf/Olof). Following the death of her father, King Valdemar, in 1375, Margrete succeeded in having her five-year-old son crowned king of Denmark. Olav also inherited the crown of Norway when his own father, Håkon, died in 1380. However, since Olav was still a minor, Margrete ruled both countries as regent. Norway formally kept its own laws, but the language of government was Danish and all higher officials were Danish. The country was increasingly ruled from Copenhagen.

When Olav died at the age of 16, Margrete was able to hold onto power and cast her gaze toward Sweden, where the nobility had begun to regret their choice of Albrekt of Mecklenburg as king, feeling their power threatened as German dominance over Sweden increased. In Stockholm Swedes who were seen as traitors to King Albrekt were murdered and burned alive by Germans who controlled the city.

The Swedish nobles turned to Margrete for help, and she responded by sending an army that defeated King Albrekt’s forces in 1389 and eventually captured Stockholm. Margrete (known as Margareta in Swedish) was proclaimed queen of Sweden, making her the regent of all three Scandinavian countries, since she already controlled Denmark and Norway following the death of her husband and son.

The Kalmar Union

Lacking any surviving children of her own, Margrete adopted her sister’s grandson, Bogislav – renamed Erik to sound more Scandinavian – of Pomerania and succeeded in having him crowned king of Denmark, Norway, and Sweden in 1397. The coronation took place in Kalmar in southeastern Sweden, and the resulting merger of the three countries became known as the Kalmar Union. However, although Erik officially became king at this time – he was 14 years old – Margrete was the de facto ruler until her death from the plague 15 years later.

In addition to Sweden, Denmark, and Norway, the Kalmar Union included Finland, which was then a part of Sweden, as well as the territories of Greenland, Iceland, and the Faroe, Shetland, and Orkney Islands, all of which were under Norwegian control. Though the center of power was located in Denmark, each kingdom and territory was largely governed according to its own laws and traditions.

Conflicts within the Union

The goal of the Kalmar Union was to stabilize political relationships both within and between the Nordic countries and strengthen mutual defenses. Although this worked relatively well under Margrete herself, the union era ultimately ended up being a time of conflicts instead. In the simplest terms, the problem was that Denmark wanted to lead and control the union, while Sweden preferred to be independent and not subject to any foreign power. One issue was that there were no unifying interests when it came to economic and foreign affairs. The Swedish nobility resisted the attempts by Erik of Pomerania and his successors to strengthen the power of the monarchy.

Another source of conflict was the Union’s relationship with the Hanseatic League. In places like Stockholm and Visby (an important trading city on Gotland) a large portion of the population at this time was made up of German merchants. At times, the Hansa also exerted a strong political influence over the Nordic countries. One of the key goals behind the Kalmar Union was a desire to enable Scandinavia to more effectively resist the mighty Hansa and the growing German domination of the region.

Both Margrete and Erik of Pomerania wanted to break the power of the Hansa and gain access to the rich trade markets of the region. Erik implemented a tax on all vessels passing through the Öresund (Øresund) strait and encouraged Swedish and Danish merchants to engage in foreign trade. The Hansa, unsurprisingly, refused to accept this and declared war on Erik. Meanwhile, workers in the iron and copper mines of central Sweden wanted to maintain strong trade with the Hansa to facilitate the export of their products. The high taxes imposed by Erik and subsequent rulers, in part to fund the war against the Hansa, led to widespread discontent, while the breakdown in trade with the League led to shortages of important goods such as salt, which was used to preserve meat and fish in an era without refrigeration.

As a result of these various issues, opposition rose in Sweden against the Danish rulers of the Kalmar Union, leading to several major rebellions and other conflicts. By 1442 Erik of Pomerania had been deposed in all three kingdoms, replaced by his sister’s son, Christoffer (Kristoffer/Kristofer) of Bavaria. For the rest of the 15th century the Swedish nobility and the Danish kings fought for power, even though the Kalmar Union officially lasted until 1523.

The End of the Kalmar Union

In the late 15th century, Sweden was ruled by a regent, Sten Sture the elder, who won a major victory against the forces of the Danish King Christian II in 1471 at the Brunkeberg Ridge in Stockholm. Sten Sture also succeeded in breaking the German control over Stockholm. Until this time, Germans had dominated high-level positions and trade in Stockholm for several centuries, while Swedes were mostly relegated to low-status jobs. From this point on, however, Swedes were able to gain access to positions at all levels.

Despite Sten Sture’s victories, King Christian II of Denmark was determined to break the power of the nobility and force Sweden back into the union. A feud between the new Swedish regent, another Sten Sture (known as the younger), who favored Swedish independence, and the archbishop, Gustav Trolle, who supported Christian, gave the Danish king his chance. In January 1520, Christian’s forces invaded the Swedish province of Västergötland and mortally wounded Sten Sture in battle.

It wasn’t long before Christian had conquered all of Sweden except Stockholm, where the widow of Sten Sture the younger was leading the defense. But in the autumn Stockholm, too, surrendered. Christian promised to forget the past and forgive his enemies, but this did not happen.

After taking Stockholm, Christian had himself crowned King of Sweden and invited all of Sweden’s leading noblemen to his coronation feast in November 1520. Gustav Trolle, who had lost both his position as archbishop and his strategically located castle of Almarestäket at the hands of Sten Sture and his supporters, was also determined to exact revenge. Trolle’s grievances provided the perfect excuse for Christian to strike against those who had opposed him and the Kalmar Union. On the third night of coronation celebrations, the palace doors were locked and the guests were brought before the king and confronted with an accounting of Trolle’s grievances. The following day, the accused, who constituted most of the Swedish nobility as well as two bishops, were condemned to death and executed in the main square of Stockholm. At least 82 people were killed in what became known as the Stockholm Bloodbath.

When Christian II returned to Denmark, he believed that opposition to the Kalmar Union was dead, but one young nobleman, Gustav Eriksson Vasa, soon emerged as a leader. Gustav’s father and other relatives were among those killed in the bloodbath, but Gustav himself – formerly a hostage of the Danish king – had not been present. Raising support from both farmers and the nobility, as well as from the Hanseatic League, Gustav launched a rebellion that eventually succeeded in defeating Christian.

Gustav was crowned King of Sweden in June 1523, and the dynasty he established went on to rule Sweden for more than a century, giving the country some of its most famous – in some cases, notorious – monarchs in history. (More on them another time!)

Norway continued in a union with Denmark until 1814, when, in the aftermath of the Napoleonic Wars, the country declared independence but was forced into a loose union with Sweden that lasted until 1905.

Key sources: SO-rummet.se, Danmarkshistorien.dk, Store Norske Leksikon

Published 15 November 2018.

Related articles:

The French Army Officer Who Became a Scandinavian King

Raiders, Traders, and Settlers: A Brief History of the Vikings

Roskilde Cathedral: Denmark’s Royal Burial Church (resting place of Margrete I)