E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Werwolf (French, loup-garou).
A bogie who roams about devouring infants, sometimes under the form of a man, sometimes as a wolf followed by dogs, sometimes as a white dog, sometimes as a black goat, and occasionally invisible. Its skin is bullet-proof, unless the bullet has been blessed in a chapel dedicated to St. Hubert. This superstition was once common to almost all Europe, and still lingers in Brittany, Limousin, Auvergne, Servia, Wallachia, and White Russia. In the fifteenth century a council of theologians, convoked by the Emperor Sigismund, gravely decided that the loup-garou was a reality. It is somewhat curious that we say a bug-bear, and the French a bug-wolf. (Wer-wolf is Anglo-Saxon, wer, a man, and wolfa man in the semblance of a wolf. Gar of gar-\??\is wer or war, a man; and ou, a corruption of orc, an ogre.)
Ovid tells the story of Lycon, King of Arcadia, turned into a wolf because he tested the divinity of Jupiter by serving up to him a hash of human flesh.
Herodotus describes the Neuri as sorcerers, who had the power of assuming once a year the shape of wolves.
Pliny relates that one of the family of Antæus was chosen annually, by lot, to be transformed into a wolf, in which shape he continued for nine years.
St. Patrick, we are told, converted Vereticus, King of Wales, into a wolf.