I found this:
"Circe and Tiresias warn Odysseus about the island of Helios, the sun god, and not to eat his sacred cattle. Against Odysseus' warnings, his men insist on landing on the island of the sun god Helios. Odysseus begs his crew to swear a solemn oath to obey this warning; and they do."
Does that sort of help. Sorry, I read that book last year an't remember it much