Before the series (known by the geeks who follow this sort of thing simply as Crisis), different religions were considered to occupy different earths within a multiverse. The most important Earths were given names, like Earth-One (home of the Silver Age gods of Ancient Greece and Rome), Earth-Two (home of the Golden Age Norse and Egyptian gods), Earth-Islam, Earth-Jew, Earth-Hindu and various others, including the ever popular Earth-Spaghetti. Pope: What do you mean you're killing Jesus off?