Having devoted a chapter to werewolves and other animal transformations in the literature of Northern Europe, Sabine Baring-Gould’s Book of Were-Wolves tries to get to the bottom of where such stories came from in chapter 4: The Origin of the Scandinavian Were-Wolf.
The author discusses textual references to berserkir (in the strictest sense, warriors in bear skin) and Ulfheðin (warriors in wolf-skin), pointing to instances of the latter in the Holmverja and Vatnsdæla Sagas. He then theorises that superstition transformed these men in the public imagination from fearsome warriors to supernatural shapeshifters. To illustrate his thesis, he returns to stories outlined in the previous chapter:
The incident mentioned in the Völsung Saga, of the sleeping men being found with their wolf-skins hanging to the wall above their heads, is divested of its improbability, if we regard these skins as worn over their armour, and the marvellous in the whole story is reduced to a minimum, when we suppose that Sigmund and Sinfjötli stole these for the purpose of disguising themselves, whilst they lived a life of violence and robbery.
In a similar manner the story of the northern “Beauty and Beast,” in Hrolf’s Saga Kraka, is rendered less improbable, on the supposition that Björn was living as an outlaw among the mountain fastnesses in a bearskin dress, which would effectually disguise him—all but his eyes—which would gleam out of the sockets in his hideous visor, unmistakably human.
Not all of Baring-Gould’s theories are as materialistic, however, as he proceeds to frame the berserkr condition as the result of demonic possession. “No fact in connection with the history of the Northmen is more firmly established, on reliable evidence, than that of the berserkr rage being a species of diabolical possession”, he writes. “The berserkir were said to work themselves up into a state of frenzy, in which a demoniacal power came over them, impelling them to acts from which in their sober senses they would have recoiled.” He also notes that the berserkir declined with the coming of Christianity.
Next, the author examines a character in Eigil’s Saga named Kveldulf, who reportedly had the ability to turn into a wolf. Baring-Gould opines that this is not a case of actual transformation, but rather “fits of diabolical possession, under the influence of which the bodily powers were greatly exaggerated”. One thing that stands out about the chapter is how it delves into etymology, this passage being typical:
Let it be observed that in these passages from the Aigla [Eigil’s Saga], the words að hamaz, hamrammr, &c. are used without any intention of conveying the idea of a change of bodily shape, though the words taken literally assert it. For they are derived from hamr, a skin or habit; a word which has its representatives in other Aryan languages, and is therefore a primitive word expressive of the skin of a beast. […] It seems probable accordingly that the verb að hamaz was first applied to those who wore the skins of savage animals, and went about the country as freebooters; but that popular superstition soon invested them with supernatural powers, and they were supposed to assume the forms of the beasts in whose skins they were disguised. The verb then acquired the significance “to become a were-wolf, to change shape.” It did not stop there, but went through another change of meaning, and was finally applied to those who were afflicted with paroxysms of madness or demoniacal possession.
Regardless of whether we accept Baring-Gould’s theory of the folkloric werewolf being a memory of the pre-Christian (and perhaps demonically-possessed) berserkir, this chapter alone distinguishes him from pseudo-historians like Elliott O’Donnell.