Why is the ninth month called September?
1580s, a form of madness (described by ancient writers) in which the afflicted thought he was a wolf, from Greek lykanthropia, from lykanthropos "wolf-man," from lykos "wolf" (see wolf (n.)) + anthropos "man" (see anthropo-). Originally a form of madness (described by ancient writers) in which the afflicted thought he was a wolf; applied to actual transformations of persons (especially witches) into wolves since 1830 (see werewolf).
lycanthropy ly·can·thro·py (lī-kān'thrə-pē)
The delusion that one is a wolf.
(from Greek lykos, "wolf "; anthropos, "man"), mental disorder in which the patient believes that he is a wolf or some other nonhuman animal. Undoubtedly stimulated by the once widespread superstition that lycanthropy is a supernatural condition in which men actually assume the physical form of werewolves or other animals, the delusion has been most likely to occur among people who believe in reincarnation and the transmigration of souls. Usually, a person is deemed to take the form of the most dangerous beast of prey of the region: the wolf or bear in Europe and northern Asia, the hyena or leopard in Africa, and the tiger in India, China, Japan, and elsewhere in Asia; but other animals are mentioned too. Both the superstition and the psychiatric disorder are linked with belief in animal guardian spirits, vampires, totemism, witches, and werewolves. The folklore, fairy tales, and legends of many nations and peoples show evidence of lycanthropic belief.