Apocalyptic literature is a literary genre originating in Judaism in the centuries following the Babylonian exile but persisting in Christianity and Islam. In apocalypse, a supernatural being reveals cosmic mysteries or the past to a human intermediary. The means of mediation include dreams, visions and heavenly journeys, and they typically feature symbolic imagery drawn from the Jewish Bible, cosmological and (pessimistic) historical surveys, the division of time into periods, esoteric numerology, and claims of ecstasy and inspiration. It is "an unveiling or unfolding of things not previously known and which could not be known apart from the unveiling". Almost all are written under pseudonyms, claiming as author a venerated hero from previous centuries, as with the Book of Daniel, composed during the 2nd century BCE but bearing the name of the legendary Daniel from the 6th century BCE.