I read a novel in the early/mid-'80s that was an attempt to place King Arthur in a more historically accurate setting. No “knights in shining armor” here; Arthur wears Roman leather armor. I don’t remember much about it. I don’t even remember if there was any magic in it; or if Merlin was just some sort of advisor. I remember that Arthur’s brother was named Kay, and that mention was made that he often used the Romanized “Kaius” (or “Kayius” or “Caius” or something like that). The title Fire King comes to mind, but when I google it I get a bunch of links to glassware.
Does anyone remember this book?