Björn (ruled 882–932) was the father of Olof (II) Björnsson and Eric the Victorious, and he was the grandfather of Styrbjörn the Strong, according to the Hervarar saga and Harald Fairhair's saga. According to the two sagas, he was the son of an Erik who fought Harald Fairhair and who succeeded the brothers Björn at Hauge and Anund Uppsale:
King Önund had a son called Eric, and he succeeded to the throne at Upsala after his father. He was a rich King. In his days Harold the Fair-haired made himself King of Norway. He was the first to unite the whole of that country under his sway. Eric at Upsala had a son called Björn, who came to the throne after his father and ruled for a long time. The sons of Björn, Eric the Victorious, and Olaf succeeded to the kingdom after their father. Olaf was the father of Styrbjörn the Strong.(Hervarar saga)
The latter saga relates that he ruled for 50 years:
There were disturbances also up in Gautland as long as King Eirik Eymundson lived; but he died when King Harald Harfager had been ten years king of all Norway. After Eirik, his son Bjorn was king of Svithjod for fifty years. He was father of Eirik the Victorious, and of Olaf the father of Styrbjorn. (Harald Fairhair's saga)
In Olaf the Holy's saga, Snorri Sturluson quotes Thorgny Lawspeaker on king Björn:
My father, again, was a long time with King Bjorn, and was well acquainted with his ways and manners. In Bjorn's lifetime his kingdom stood in great power, and no kind of want was felt, and he was gay and sociable with his friends. (Saga of Olaf Haraldsson)
When Björn died, Olof and Eric were elected to be co-rulers of Sweden. However, Eric would disinherit his nephew Styrbjörn.
Adam of Bremen, however, only gives Emund Eriksson as the predecessor of Eric the Victorious. Since the Swedes seem to have had a system of co-rulership (Diarchy), it is probable that Emund Eriksson was a co-ruler of Björn's.
His name, Björn, means bear in Swedish.