Valdemar Birgersson (1239–1302), English also Waldemar, King of Sweden 1250–1275/1288/1302, was the son of princess Ingeborg Eriksdotter of Sweden and Birger jarl, a.k.a. Birger Magnusson from the House of Bjelbo, who more or less ruled Sweden from 1248 under king Eric Ericsson the Lame, his brother-in-law. When king Eric XI died in 1250, Valdemar was elected king, while Birger jarl was presumably on a campaign in Finland.

Even after the coming of age of Valdemar in 1257, Valdemar's father Birger jarl held a grip over the country. After Birger's death in 1266 Valdemar came into conflict with his younger brother duke Magnus, who wanted the throne for himself.

Valdemar had a relationship with his queen's sister Jutta (both of them princesses of Denmark) and had to go to Rome in order to get the Pope's forgiveness. In 1288 he was imprisoned by his brother Magnus, who had usurped his throne, being elected king in 1275.

Family

Valdemar married Sofia of Denmark (d. 1286) in 1260 and separated in 1277. He had six children:

• Ingeborg Valdemarsdotter of Sweden (1263–1292), countess of Holstein, spouse of Gerhard II of Holstein.

• Erik Valdemarsson of Sweden (1272–1330)

• Marina Valdemarsdotter of Sweden, spouse of Count Rudolf of Diepholz

• Rikissa Valdemarsdotter of Sweden (d. c. 1292), Queen of Poland, spouse of Przemysł II of Poland

• Katarina Valdemarsdotter of Sweden (d. 1283)

• Margareta Valdemarsdotter of Sweden, a nun.