In 1632, Erik Johan Prytz, vicar of Linköping, Sweden, wrote that people would frequently strike deals with nature spirits such as forest nymphs and water spirits in order to learn sorcery, for success in hunting and fishing, and for luck generally (Hall 28).
The evidence, not just from Sweden, but from all over Europe, bears him out.
Swedish sorcerer Matts Larsson was accused in 1685 of having intimate relations with a bergrået, a mountain nymph (Hall 30).
In 1697, the infamous sorcerer Jon of Hallebo confessed that he had received a book of magic from “the man in the stream,” a water spirit known in Swedish as strömkarlen (Hall 32).
The notorious outlaw Tidemann Hemmingsson was also accused of having concluded a pact with a “forest maiden,” a skogsrået, which reportedly granted him good luck in hunting (Hall 35).
In 1653, cunning woman Karin Persdotter confessed to having learned her sorcery from a male water spirit, called variously the "man of the stream" (strömkarlen), the "nix" (näcken), or "the river" (älven) (Hall 32).
As late as 1699, renegade soldier Simon Simonsson Brynt confessed to having received supernatural proficiency at fishing by virtue of a pact with a forest nymph, with whom he had had carnal relations for some three years (Hall 36).
Examples could be multiplied from virtually everywhere across Europe: Scotland (Wilby 112ff), England, Germany, Italy (Henningsen 191ff), Rumania (Eliade 149ff), and Hungary (Pócs 49ff), to name only some.
It would seem that virtually everywhere in pre-modern times, certain people in any given society were wont to derive magical powers from a relationship with what we may call wights: elves, fairies, nature spirits. Hungarian historian Éva Pócs writes that this would appear to be the underlying folkloric original of the witch's pact, later diabolized during the Great Persecution.
At the easternmost end of the Indo-European diaspora, shamans (dehár) among the Kalasha of Pakistan, the last surviving pagans of the Hindu Kush, derive their powers from their association with the mountain “fairies” (suchi, peri) (Lièvre 72ff).
It can hardly be doubted that we see here an archaic cultural trope of deepest antiquity which lived on into Early Modern times.
Nor can it be doubted that this fact has profound implications for the practice of contemporary witchcraft.
But then, you didn't need me to tell you that.
Eliade, Mircea, “Some Observations on European Witchcraft,” in History of Religions 14 (1974).
Hall, Mikael, “'It is Better to Believe in the Devil': Conceptions of Satanists and Sympathies for the Devil in Early Modern Sweden,” in The Devil's Party, ed. Per Faxheld and Jesper Aa Petersen (2013). Oxford.
Henningsen, Gustav, “'The Ladies from Outside': An Archaic Pattern of the Witches' Sabbath,” in Early Modern European Witchcraft: Centres and Peripheries (1998), ed. Ankarloo and Henningsen. Oxford.
Lièvre, Viviane and Jean-Yves Loude, Le Chamanisme des Kalash du Pakistan: Des Montagnards Polythéistes Face à l'Islam (1990). University of Lyon Press.
Pócs, Éva, Between the Living and the Dead (1999). CEU Press.
Although we share a surname—in its Hungarian and Austrian forms respectively—Éva and I are not (to the best of my knowledge) related. But (in the wide realm of all possibility) who knows?
Wilby, Emma, Cunning Folk and Familiar Spirits: Shamanistic Visionary Traditions in Early Modern British Witchcraft and Magic (2005). Sussex University Press.