No one knows how the belief in fairies began. In some stories, fairies were angels who were forced to leave heaven because of some wrongdoing. In other stories, fairies were spirits of the dead. Some scholars believe that fairies began as ancient nature spirits, such as the spirits of the mountains, streams and trees. Many stories about the fairies represent attempts to explain various happenings. For example, if a cow goes dry for no apparent reason, a farmer may blame fairies for stealing her milk.