Mythology refers variously to the collected myths of a group of people or to the study of such myths. A folklore genre, myth is a feature of every culture. Many sources for myths have been proposed, ranging from personification of nature or personification of natural phenomena, to truthful or hyperbolic accounts of historical events to explanations of existing rituals. A culture's collective mythology helps convey belonging, shared and religious experiences, behavioral models, and moral and practical lessons. The study of myth began in ancient history. Rival classes of the Greek myths by Euhemerus, Plato and Sallustius were developed by the Neoplatonists and later revived by Renaissance mythographers. The nineteenth-century comparative mythology reinterpreted myth as a primitive and failed counterpart of science, a "disease of language", or a misinterpretation of magical ritual.