Erik was born around 1282, the second son of King Magnus Ladulås of Sweden and his queen consort, Helvig of Holstein.

In 1284, as his elder brother Birger was designated as the future king, Erik was granted the title of duke, receiving Södermanland and part of Uppland as his fief.

[citation needed] King Birger, who feared his brothers' plans, forced them to sign a paper, in 1304, so as to render them less dangerous.

Through his strategic skills, Erik managed to ride out the storm, and defeated the Norwegians, and also the Danes who arrived as far as Nyköping in 1309.

Erik received Västergötland, Dalsland, Värmland and Kalmar County, as well was northern Halland as a fief from Denmark, but he promised to return Kungahälla to Norway.

At the same ceremony, Erik's brother Valdemar married Ingeborg Eriksdottir, the daughter of King Eric II of Norway.

However, his career was stopped and his life was shortened by the treachery of his brother King Birger, the de jure ruler of Sweden.

On 16 April 1318, the two duchesses entered into a treaty in Kalmar with Esger Juul, Archbishop of Lund and Christopher, brother of Eric VI of Denmark and Duke of Halland-Samsö, to free their husbands.

Its authorship and precise political significance and biases are debated, but it is clear that the chronicle's main protagonist and hero is Erik.

[3] This article contains content from the Owl Edition of Nordisk familjebok, a Swedish encyclopedia published between 1904 and 1926, now in the public domain.