Björn Ironside , according to Norse legends, was a Norse Viking chief and Swedish king. According to the 12th- and 13th-century Scandinavian histories, he was the son of notorious Viking king Ragnar Lodbrok and lived in the 9th century AD, attested in 855 and 858. Björn Ironside is said to have been the first ruler of the Swedish Munsö dynasty. In the early 18th century, a barrow on the island of Munsö was claimed by antiquarians to be Björn Järnsidas hög or Björn Ironside's barrow.
Medieval sources refer to Björn Ironside's sons and grandsons, including Erik Björnsson and Björn at Haugi. Icelandic sagas claim that Björn was the ancestor of the house of Munsö, the line of kings that ruled in Sweden until c. 1060.
