Dear Bernhard Cornwell.
I have read many of your books with great joy, and there are many more I have not read yet.
I am currently in the "Utred modus", and I have to thank you very much for making me understand much more of the influence in Britain and Ireland by the Scandivavian vikings. Together with the great book by Bergsveinn Birgsson "(The Black Viking)(ISBN:978-82-430-0812-0) I gain a much better understanding of what could be the reality.
I myself grew up in mid west of Norway, in the old area of the "Møre Jarl", just south of Trondheim. A boat grave of a "free farmer" was found just 200m from my home place,close to the current church yard, and the area was/is a nice farmland upstream a river.
Now I come to a point that both you and Bergsveinn Birgsson are dwelling with, and also Wikipedia does not have much information.
The name "Beinlause, or Beinlausi,, or Boneless.
-For myself, I think your description of Ivarr is the most realistic. The reason I think so is as follows:
When I grew up in the early 60's, particularly my mother very often said; listen; it is "han beinlaus som går", meaning it's him; the "boneless walking"
The meaning of this was when we could hear a door moving or a window slapping without a human intervention,, meaning often the draft; it was common to say it was "Him the Boneless". "Han Beinlaus"
When reflecting upon this, it could give assosiations to a ghost, or a phantom, or someone which was so tiny and light that it was difficult to notice him doing it.
Or someone very clever to move unoticed, as you described Uthered while he was young.
But my mother in law suddenly came with another expression out of the air. Have never heard it or expected it: We live now besides Hafrsfjord, where Harald Hårfagre defeated the other Norwegian kings as you know.
We where sitting discussing some other people, and she suddently said; he was soo thin that you could not see the legs inside his trousers,,, he was like "Ivarr Beinlause". ( she is soon 90years old) This is the other setting I have heard the name mentioned.
My personal conclusion is therefore that your description of Ivarr is very correct, and maybe he was a specialist in moving around unseen and unnoticed as well.
He could have been so, and if my mothers saying was a heritage from Ivarr himself, he must have been.
However, my mothers saying could have been a general saying of this phenomena, and that this gave the name to Ivarr as he could move unseen, but it would help to be very thin and light...., hence, maybe a combination.
-Now my wish: Hopefully this can fill in for what you have found of information earlier. My wish is that you in power of your person propose to update the information in Wikipedia, so that people can have more information to draw an conclusion towards the origin of Ivarr's name.
The reason.... The reason is that I feel ashamed of the person they make up in "The Vikings" describing Ivarr Beinlause. I think it is absolute out of the concept to present him with paralyzed legs, and it disturbs the story, and also make people fetch wrong impressions of a formidable worrier.
Well, I do not expect you to do anything, as this is definitely not research, but i have had this on my heart for a long while, and I feel much better by telling you this. At least I can share it with someone that can have an objective view of the information avaliable at Wikipedia.
Wish you have a Merry Christmas. I will be going trough the "Flame Bearer" during this time, enjoying a lot.
Thank you very much.
Best regards
Lyder Moen.