Voltaire is often thought of as an athiest, although he did in fact take part in religious activities and even built a chapel at his estate at Ferney. The chief source for the misconception is a line from one of his poems (called "Epistle to the author of the book, The Three Impostors") which is usually translated as: "If God did not exist, it would be necessary to invent Him". Many commentators have argued that this is an ironical way of saying that that it does not matter whether God exists or not, although others claim that it is clear from the rest of the poem that any criticism was more focused towards the actions of organized religion, rather than towards the concept of religion itself. http://www.philosophybasics.com/philosophers_voltaire.html