Born in 1280, died 1321, Birger was the son of Magnus Ladulås and king of Sweden from 1290 to 1318. After insistence on part of his brothers, the dukes Erik and Valdemar, he had Torgils Knutsson executed in 1306. Later that year, Birger was imprisoned at Håtuna in southern Uppland by his brothers (Håtunaleken) and taken to Nyköping where he stayed prisoner until 1308, when he was forced to submit the kingdom to his brothers. Birger was free now, and fled to Denmark from where he returned in 1310. With danish and norwegian support, he managed to reclaim parts of his former kingdom. At a Nyköpings gästabud, a deceitful event that Birger held in 1317 at the castle, Erik and Valdemar were unsuspectedly imprisoned in the castle tower and left to die, but their supporters rebelled and Birger was yet again forced to flee to Denmark, where he later died. Birger's son, Magnus, was sentenced to death and executed in 1320.