Eaters of the Dead
Eaters of the Dead is a 1976 novel by Michael Crichton.
Crichton drew upon ambassador Ibn Fadlan's account of his journeys among the early Russians, and posits the origin of the Beowulf epic as a conflict between Vikings and a small relict Neanderthal population.
"I wrote Eaters on a bet that I could make an entertaining story out of 'Beowulf'. It's an unusual book. Readers either like it, or they don't," writes Crichton. [1]
The novel was adapted into film as The 13th Warrior, directed by John McTiernan, with Antonio Banderas as Ibn Fadlan. Crichton writes that he was "quite pleased" with the film, though it earned mixed reviews and performed rather poorly at the box office, earning about $32 million; the film's budget was over $80 million.