Erik Birgersson

Erik Birgersson (c. 1250 – 17 December 1275) was a Swedish duke from the House of Bjälbo (Folkungaätten) and the third son of Birger Jarl. His eldest brother, Valdemar, was elected King of Sweden, while his second brother, Magnus, was made a duke. Unlike his brothers, Erik initially held no formal title, which became a source of frustration. Discontent over the distribution of power ultimately led him and Magnus to rebel against King Valdemar. Together, they defeated him at the Battle of Hova in 1275, resulting in Magnus being crowned king and Erik assuming the title of duke. However, Erik died only months after gaining his newfound position of power. It has been suggested that Erik may have suffered from Marfan syndrome, a genetic disorder affecting connective tissue.