Erik Birgersson

Erik Birgersson (c. 1250 – 17 December 1275) was a Swedish duke of the House of Bjälbo (Folkungaätten).^[1][2]

His father was Birger Magnusson (Birger Jarl), Jarl of Sweden and de facto ruler of Sweden from 1250–66. His mother was Ingeborg of Sweden, daughter of King Erik Knutsson and sister of King Erik Eriksson.^[3][4][5]

According to the Magnúss saga lagabœtis, Erik called himself "Eirek allz-ekki" because he had no title.^[6] In the conflict between his elder brothers, Valdemar and Magnus, he sided with Magnus. After Magnus emerged victorious and was proclaimed king in 1275, Erik was made Duke of Småland. He died shortly afterwards.^[7]

Erik was buried at Varnhem Abbey alongside with his father Birger Jarl and his father's second wife, Mechtilde of Holstein. When the grave was opened and examined in May 2002, osteologist Torbjörn Ahlström from Lund University confirmed that the tomb contained the remains of three people – probably Birger, Mechtilde, and Erik. His father's skeleton shows that he was about 172 cm long, while Erik was a few inches longer but with a much thinner build. Erik's muscular attachments were poorly developed. In the vertebrae and sternum there were some signs of pathological changes.^[8] Ahlström suggested that Erik may have had Marfan's syndrome, a hereditary genetic disorder that affects the connective tissue.^[9] It has been speculated that his uncle, King Erik Eriksson, nicknamed "the lisp and the lame", may have had the same condition.^[10]

• Rolf Pipping, Kommentar till Erikskrönikan (Helsingfors 1926).