Erik, Duke of Mecklenburg

Erik, Duke of Mecklenburg (c. 1367/1368 – 26 July 1397) was the eldest son and heir apparent of Albert, King of Sweden.

Erik was the eldest son of Albert, King of Sweden (r. 1364–1389), and Queen Richardis, daughter of Count Otto I of Schwerin.

This is inferred from a contemporary genealogy that records Albert's betrothal and succession to the throne in 1364 but does not mention the marriage, suggesting it had not yet occurred.

Viljo Nordman speculates that Erik was of legal age, eighteen, in 1385–1386, when he first appears in documents, placing his birth to 1367–1368.

[4] In 1389, Queen Margaret I of Denmark defeated Albert in the battle of Åsle, on the plains of Falköping in Västergötland.

In 1395, Albert and Erik were released against a large ransom after three years of negotiations involving Hinrich Westhof and Johann Niebur, the mayors of Lübeck.

In the spring of 1397, with the help of Victual Brothers, Erik defeated Sven Sture, who was forced to change sides and swear allegiance to Albert III.

[12] In June 1397 Erik, accompanied by Sven Sture's men, launched a failed surprise attack against Stockholm, now controlled by the Hanseatic league.

[13] Around the same time, the kingdoms of Denmark, Norway and Sweden were united into the Kalmar Union, which cemented the position of Queen Margaret and crushed Mecklenburg's hopes of regaining the Swedish crown.

In 1397, Duke Erik suddenly died of an illness at his fortress, called Landeskrone or Klinteholm, located close to the port of Klintehamn, south of Visby in Gotland.

The fortress of Landeskrona was destroyed in 1398 when the Teutonic Order and the leading Prussian cities conquered the island to put an end to piracy.