First Swedish–Norwegian union

The First Swedish–Norwegian union was a personal union between the kingdoms of Sweden and Norway. The union was established in 1319, when the three-year-old Magnus Eriksson was elected King of Sweden and at the same time inherited the Norwegian throne from his maternal grandfather, King Haakon V. At the time, Sweden included Finland, while Norway encompassed its overseas colonies: Iceland, Greenland, the Faroe Islands and the northern isles of Orkney and Shetland. In 1332, Magnus also acquired Skåne from Denmark.

The dissolution of this union was a complex and gradual process. A formal decision to dissolve the union was made at the Varberg agreement of 1343, which arranged for the future succession of separate kings for Norway and Sweden. Despite this, the union persisted in some form until the late 14th century, as Magnus Eriksson continued to act as King of Norway alongside his son, Haakon, who became King of Norway in 1355. Haakon was also elected King of Sweden in 1361. In 1363–1364, a rebellion deposed Magnus and Haakon and elected Albrecht of Mecklenburg as King of Sweden, but they nevertheless retained control over Norway and parts of western Sweden. The union was formally broken when Haakon died in 1380.

The Swedish–Norwegian union set the stage for the creation of the Kalmar Union, which brought Sweden, Norway, and Denmark under a single crown. The union was established by Margaret, Haakon's widow and daughter of King Valdemar IV of Denmark, who successfully consolidated the three kingdoms under her rule in 1389.