At Christmas a boy lame of a leg goes round the country summoning the devil’s followers, who are countless, to a general conclave. Whoever remains behind, or goes reluctantly, is scourged by another with an iron whip till the blood flows, and his traces are left in blood. The human form vanishes, and the whole multitude become wolves. Many thousands assemble. Foremost goes the leader armed with an iron whip, and the troop follow, “firmly convinced in their imaginations that they are transformed into wolves.” They fall upon herds of cattle and flocks of sheep, but they have no power to slay men. When they come to a river, the leader smites the water with his scourge, and it divides, leaving a dry path through the midst, by which the pack may go. The transformation lasts during twelve days, at the expiration of which period the wolf-skin vanishes, and the human form reappears. This superstition was expressly forbidden by the church. “Credidisti, quod quidam credere solent, ut illæ quæ a vulgo Parcæ vocantur, ipsæ, vel sint vel possint hoc facere quod creduntur, id est, dum aliquis homo nascitur, et tunc valeant illum designare ad hoc quod velint, ut quandocunque homo ille voluerit, in lupum transformari possit, quod vulgaris stultitia, werwolf vocat, aut in aliam aliquam figuram?”–Ap. Burchard. (d. 1024).
From Sabine Baring-Gould’s marvelous volume The Book of Were-Wolves (1865).