Kalmar Union Is Formed Summary

  • Last updated on November 11, 2022

The Kalmar Union was formed through the diplomatic skills of Margaret I, bringing Sweden, Norway, and Denmark under the rule of a single sovereign in a union that lasted more than a century.

Summary of Event

During the fourteenth century, the three Scandinavian nations of Denmark Denmark , Norway Norway , and Sweden Sweden were involved in numerous complex struggles for political power. In addition to wars among the three nations and conflicts between the nations of Scandinavia and the Hanseatic League Hanseatic League (a powerful federation of German trading towns), there were internal struggles as well. [kw]Kalmar Union Is Formed (June 17, 1397) Kalmar Union Margaret I of Denmark, Norway, and Sweden Scandinavia;June 17, 1397: Kalmar Union Is Formed[3050] Government and politics;June 17, 1397: Kalmar Union Is Formed[3050] Trade and commerce;June 17, 1397: Kalmar Union Is Formed[3050] Diplomacy and international relations;June 17, 1397: Kalmar Union Is Formed[3050] Laws, acts, and legal history;June 17, 1397: Kalmar Union Is Formed[3050] Albert (1340-1412) Margaret of Denmark, Norway, and Sweden Erik of Pomerania Christian II Gustav I Vasa

During one of these struggles, the nobles of Sweden, in alliance with the Hanseatic League, invited Albert Albert (king of Sweden) of Mecklenburg, a German prince, to drive out the current king of Sweden, Magnus II Magnus II (king of Sweden) , who was his uncle. Albert invaded in 1363, taking the title of king. He defeated the forces of Magnus II in 1365 and took him prisoner. Magnus II was released in 1371 in exchange for recognizing Albert as king.

The reign of Albert was a constant struggle with the Swedish nobles, who held most of the real power. The most powerful of these nobles was Bo Jonsson Grip, who owned large amounts of land in Sweden, including all of Finland (which was at the time a part of Sweden). When Grip died in 1386, Albert attempted to seize his estates, and this act caused the nobles to unite against him.

Meanwhile, the future ruler of all three nations was consolidating her own power. The daughter of King Valdemar IV Valdemar IV (king of Denmark) of Denmark, Margaret I married King Hákon VI Hákon VI (king of Norway) of Norway, the son of Magnus II, in 1363, when she was ten years old. During the reign of Albert, Hákon VI lost his claim to the throne of Sweden but retained Norway.

In 1370, Margaret gave birth to a son, Olaf. When Valdemar IV died in 1375, she was able to convince the nobles of Denmark to elect Olaf king. Because he was still a child, Margaret ruled Denmark as regent in his place.

In 1380, Hákon VI died and Olaf Olaf II (king of Denmark and Norway) inherited the throne of Norway. Margaret was now the regent of both Denmark and Norway. When the Swedish nobles turned against Albert in 1386, Margaret was ready to offer military aid to them in exchange for making Olaf king of Sweden as well. Her plans were destroyed when Olaf died suddenly on August 3, 1387, possibly from poison.

During this crisis, Margaret proved to have great skill at diplomacy. She had no claim to the throne of any of the three nations, and Scandinavian law and tradition prevented a woman from reigning as a monarch. Despite this restriction, she managed to persuade the nobles of both Denmark and Norway to allow her to continue to rule as regent, with the right to name her heir. The heir she chose was her grandnephew, Erik of Pomerania Erik of Pomerania , who was a young child at the time.

In March of 1388, the Swedish nobles accepted Margaret as regent of Sweden also, beginning a war for control of Sweden between Margaret and Albert. On February 24, 1389, a decisive battle was fought near the Swedish town of Falköping Falköping, Battle of (1389) . The forces of Margaret defeated the forces of Albert, and he was taken prisoner. Margaret was now the ruler of all three Scandinavian nations.

The Swedish city of Stockholm continued to be controlled by the supporters of Albert. These supporters allied themselves with pirates who were disrupting trade on the Baltic Sea. The Hanseatic League, which depended on the Baltic trade routes, formed an alliance with Margaret against the pirates. In 1395, Margaret made an agreement with the supporters of Albert to release him from imprisonment in exchange for a large ransom. If the ransom was not paid, Stockholm would be turned over to the Hanseatic League for three years, after which it would be given to Margaret. Albert was unable to raise enough money for the ransom, so the Hanseatic League took over the city and spent the next three years destroying the pirates.

Erik of Pomerania was accepted as king of Norway in 1389, and was elected king of Denmark and Sweden in 1396. On June 17, 1397, representatives of all three nations, nobles and clergymen, gathered at Kalmar, Sweden, to witness the coronation of Erik of Pomerania as the king. This ceremony was the birth of what would later be known as the Kalmar Union.

Little is known of the negotiations that took place between Margaret and the nobles at Kalmar at this time, but they seem to have taken about a month to complete. The two documents produced by these negotiations were both dated July 13, 1397. The first document, known as the Coronation Letter, was written on parchment and announced the coronation of Erik of Pomerania in a way that implied a centralized, hereditary monarchy.

The second document, known as the Union Letter, has been closely studied by historians because it poses several questions. Although the text of this document states that it is written on parchment and that it is hung with seventeen seals, it is actually written on vellum and contains only ten seals, which are stamped into it rather than hanging from it. These discrepancies, along with the fact that the Union Letter contains written corrections, leads scholars to believe that it is an unapproved draft of an agreement that was never completed.

Apparently Margaret wanted a closer union of the three nations than the nobles, who wanted to ensure that each nation would retain its own laws and customs. Unable to come to a formal agreement with the nobles about the exact details of the union, Margaret continued to rule as before, relying on her diplomatic skills to avoid conflicts.

Although Erik of Pomerania reached the age at which he no longer needed a regent in 1401, Margaret remained the unofficial power behind the throne until her death on October 28, 1412. She spent the last years of her life strengthening the union and increasing the power of the sovereign by appointing loyal and efficient officials to administer her government.

Erik of Pomerania proved to be a less effective ruler than Margaret. His attempt to build an empire on the Baltic coast led to an expensive war with the Hanseatic League. A blockade of Swedish exports of iron and copper by the Hanseatic League in 1434 led to a rebellion by Swedish miners. Eventually Erik of Pomerania was deposed from the thrones of Denmark and Sweden in 1439 and Norway in 1442.

Erik of Pomerania was replaced by Christopher III, who died in 1448 with no heir. Danish nobles selected Christian I as his successor while Swedish nobles selected Karl Knutsson. The conflict between Denmark and Sweden continued for the next several decades, as one side or the other gained control over the throne of Sweden.

On January 19, 1520, Christian II Christian II (king of Denmark, Norway, and Sweden) , the king of Denmark and Norway, defeated the forces of Sten Sture the Younger Sten Sture the Younger , the regent of Sweden. After months of attempting to take the city of Stockholm by force, Christian II convinced it to surrender by promising amnesty to his opponents. He was crowned king of Sweden on November 4, 1520. Four days later, despite his promise of amnesty, he executed eighty-two supporters of Sten Sture the Younger in an event later known as the Stockholm Bloodbath Stockholm Bloodbath (1520) . The bloodbath alienated most Swedish factions, and the union was in great disfavor.

The Swedish nobleman Gustav I Vasa Gustav I Vasa led a war of independence against Christian II, defeating him with the financial help of the rich German trading city of Lübeck. He was crowned king of Sweden on June 6, 1523, ending the Kalmar Union.


Despite Margaret’s diplomacy and tact, the Kalmar Union never formally materialized. What was significant about Margaret’s attempts to bring the three nations together is their turning back a German (Hanseatic League) economic and cultural advance into Scandinavia and the Baltic region. Also, Scandinavia remained a great union under one sovereign, one of Margaret’s goals, for more than one hundred years.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Butler, Ewan. “Royal Union, Peasant Separatism.” In The Horizon Concise History of Scandinavia. New York: American Heritage, 1973. Focuses on the wars and rebellions that threatened the Kalmar Union throughout its history.
  • citation-type="booksimple"

    xlink:type="simple">Derry, T. K. “The Union of Three Crowns.” In A History of Scandinavia. Minneapolis: University of Minnesota Press, 1979. A detailed account of the rise and fall of the Kalmar Union. Gives a contextual discussion on life in the Middle Ages. Includes maps, family trees, and a helpful time line of parallel events in all the Scandinavian countries. Excellent bibliography.
  • citation-type="booksimple"

    xlink:type="simple">Larsen, Karen. “Scandinavian Union.” In A History of Norway. 1948. Reprint. Princeton, N.J.: Princeton University Press, 1974. An account of the Kalmar Union from the viewpoint of Norway.
  • citation-type="booksimple"

    xlink:type="simple">Sawyer, Birgit, and Peter Sawyer. Medieval Scandinavia: From Conversion to Reformation, Circa 800-1500. Minneapolis: University of Minnesota Press, 1993. Provides a history of Scandinavia in the Middle Ages, from its lands and people, to its politics, trade, towns, religions, ancestry, and more. Maps, bibliography, index.
  • citation-type="booksimple"

    xlink:type="simple">Scott, Franklin D. “Margareta and the Union of Kalmar.” In Sweden: The Nation’s History. Carbondale: Southern Illinois University Press, 1988. Discusses Margaret I and the Kalmar Union as seen by Sweden. Includes maps, bibliography, and index.
  • citation-type="booksimple"

    xlink:type="simple">Singleton, Fred. “Finland and Sweden.” In A Short History of Finland. 2d ed. Cambridge, England: Cambridge University Press, 1998. Describes the effect of the Kalmar Union on Finland.

Categories: History