Mithra — like Tammuz, Adonis, Apollo and Horus — was a sun-god. So you see, the "reason for the season" is not the son of any god, but the sun up in the sky!
King told a German magazine that, yes, he can always learn something new. With one exception — if it comes to religious topics everything is already said. I am an agnostic, so I don't learn anything from them."