I think we can all agree that the tv show is fantastic, albeit somewhat historically inaccurate. I just have several questions about the historical Ragnar, and his descendants.

1. Is there enough evidence to support that Ragnar was an actual historical figure? Or is/was he pretty much a semi-legendary character? Or is he an amalgamation of several historical figures that lived during the Viking age?

2. Do any of the sources make direct reference to Ragnar, and do they discuss his campaigns/raids in depth? As a warrior and commander, where does he rank among other Viking chieftains?

3. Odd question, and maybe this goes hand in hand with question number one, but was he of Danish or Norse descent?

4. We do know of his sons, or his supposed sons - those being Ubba, Halfdan, Björn Ironside, Sigurd Snake-in-the-Eye, and Ivar the Boneless. Were they actual sons of the historical Ragnar? If not, why did they claim descent from him? Wasn't Ubba of Frisian descent, why would he claim descent from a Dane?

5. Of all the Loðbrók sons, who was the most successful commander?

Thanks