An interesting article at Apolyton about the remnants of religions in Civ5 And no, it are not leftovers from Civ4's xml's or anything. Have a look Very interesting indeed! It looks like they really were planning on including it, but probably couldn't make it budget- or time-wise (I don't believe the "it doesn't fit the diplomacy'-excuse). Utterly interesting. Maybe they'll include it eventually in an expansion?