When Björn dies in Vikings, it brings up questions about the characters' historical counterparts and if their deaths on the show matched up to real life and historical legend. Vikings initially followed Ragnar Lothbrok, a legendary Norse figure who is said to have been one of the greatest Vikings to ever live. Yet, his existence continues to be debated by historians. As the series progressed, it shifted its focus to Ragnar’s sons, with special attention to the arcs of Björn Ironside and Ivar the Boneless.
https://screenrant.com/vikings-show-characters-deaths-norse-mythology-legends-comparison/