Ragnar Lothbrok: Legendary Hero or Historical Figure?
According to legend, Ragnar Lothbrok was a king of Denmark who succeeded Sigurd Hring in 804 AD. Some historians identify him with Reginherus, a Norse chieftain who was responsible for the siege of Paris in 845 AD. There are historians, however, who dispute this idea. Either way, Ragnar is probably partly historical and partly legendary, like many figures in Scandinavian prehistory.
Source: ancient-origins.net