Styrbjörn the Strong according to late Norse sagas was a son of the Swedish king Olof Björnsson, and a nephew of Olof's co-ruler and successor Eric the Victorious, who defeated and killed Styrbjörn at the Battle of Fyrisvellir. As with many figures in the sagas, doubts have been cast on his existence, but he is mentioned in a roughly contemporaneous skaldic poem about the battle. According to legend, his original name was Björn, and Styr-, which was added when he had grown up, was an epithet meaning that he was restless, controversially forceful and violent.