A fairy tale, fairytale, wonder tale, magic tale, fairy story or Märchen is an instance of folklore genre that takes the form of a short story. Such stories typically feature mythical entities such as dwarfs, dragons, elves, fairies and Peris, giants, Divs, gnomes, goblins, griffins, mermaids, talking animals, trolls, unicorns, or witches, and usually magic or enchantments. In most cultures, there is no clear line separating myth from folk or fairy tale; all these together form the literature of preliterate societies. Fairy tales may be distinguished from other folk narratives such as legends (which generally involve belief in the veracity of the events described) and explicit moral tales, including beast fables. In less technical contexts, the term is also used to describe something blessed with unusual happiness, as in 'fairy-tale ending' (a happy ending) or 'fairy-tale romance'. Colloquially, the term 'fairy tale' or 'fairy story' can also mean any far-fetched story or tall tale; it is used especially of any story that not only is not true, but could not possibly be true. Legends are perceived as real within their culture; fairy tales may merge into legends, where the narrative is perceived both by teller and hearers as being grounded in historical truth. However, unlike legends and epics, fairy tales usually do not contain more than superficial references to religion and to actual places, people, and events; they take place 'once upon a time' rather than in actual times. Fairy tales occur both in oral and in literary form; the name 'fairy tale' ('conte de fées' in French) was first ascribed to them by Madame d'Aulnoy in the late 17th century. Many of today's fairy tales have evolved from centuries-old stories that have appeared, with variations, in multiple cultures around the world. The history of the fairy tale is particularly difficult to trace because only the literary forms can survive. Still, according to researchers at universities in Durham and Lisbon, such stories may date back thousands of years, some to the Bronze Age. Fairy tales, and works derived from fairy tales, are still written today. The Jatakas are probably the oldest collection of such tales in literature, and the greater part of the rest are demonstrably more than a thousand years old. It is certain that much (perhaps one~fifth) of the popular literature of modern Europe is derived from those portions of this large bulk which came west with the Crusades through the medium of Arabs and Jews. Folklorists have classified fairy tales in various ways. The Aarne-Thompson classification system and the morphological analysis of Vladimir Propp are among the most notable. Other folklorists have interpreted the tales' significance, but no school has been definitively established for the meaning of the tales. The fairy tale, told orally, is a sub-class of the folktale. Many writers have written in the form of the fairy tale. These are the literary fairy tales, or Kunstmärchen. The oldest forms, from Panchatantra to the Pentamerone, show considerable reworking from the oral form. The Grimm brothers were among the first to try to preserve the features of oral tales. Yet the stories printed under the Grimm name have been considerably reworked to fit the written form.