Re: Huon a knight of IT?
Oh, so Andre Norton didn't make it all up in "Huon of the Horn" (1951) which I described in a comment above. Although that implies that somebody else did.
Wikipedia: "The poem tells of Huon, a knight who unwittingly kills Charlot, the son of Emperor Charlemagne. He is given a reprieve from death on condition that he fulfil a number of seemingly impossible tasks: he must travel to the court of the Emir of Babylon and return with a handful of the Emir's hair and teeth, slay the Emir's mightiest knight, and three times kiss the Emir's daughter, Esclarmonde. Huon eventually accomplishes all these feats with the assistance of the fairy king Oberon." Sorry, what?
Andre Norton's version is, according to what I take as the book cover, just like that. Norton's Huon kills Charlot who attacked Huon and his brother apparently without provocation. Charlot had it coming, but Charlot was maybe king and his father was Emperor, so there were consequences.
In real life, or in Wikipedia, Charlemagne divided his empire among his sons, his son Charles, or "Charles the Younger", or "Charlot" in that sort of thing, was designated King of the Franks. Charles the Younger died of a stroke aged 39, which is bad luck and/or the consequence of a surfeit or something.