Werewolves, also known as lycanthropes, are mythological or folkloric people with the ability to shapeshift into a wolf or wolflike creature, either purposely, by using magic, or after being placed under a curse. The medieval chronicler Gervase of Tilbury associated the transformation with the appearance of the full moon; however, there is evidence that the association existed among the Ancient Greeks, appearing in the writings of Petronius. This concept was rarely associated with the werewolf until the idea was picked up by fiction writers. Shape-shifters similar to werewolves are common in tales from all over the world, though most of them involve animal forms other than wolves. Werewolves are a frequent subject of modern fictional books and films, although fictional werewolves have been attributed traits distinct from those of original folklore, most notably the vulnerability to silver bullets. They originated in Germany, and there were si