In Old Norse, seiðr (sometimes anglicized as seidhr, seidh, seidr, seithr, seith, or seid) was a type of magic practiced in Norse society during the Late Scandinavian Iron Age. The practice of seiðr is believed to be a form of magic which is related to both the telling and the shaping of the future. Connected to the Old Norse religion, its origins are largely unknown, and its practice gradually declined after the Christianization of Scandinavia. Accounts of seiðr later made it into sagas and other literary sources, while further evidence of it has been unearthed by archaeologists. Various scholars have debated the nature of seiðr, some of them have argued that it was shamanic in context, involving visionary journeys by its practitioners.
Seiðr practitioners were of both sexes, with sorceresses being variously known as vǫlur, seiðkonur and vísendakona. There were also accounts of male practitioners, who were known as seiðmenn (or seiðmaðr in the singular). In many cases these magical practitioners would have had assistants to aid them in their rituals.
