When Christianity first entered the Nordic regions, the Norsemen did not have any particular name for their religious practices. To set those old practices apart from the new Christian tradition, Christianized Noblemen began to refer to their ancestral practices as the Old Custom (Forn Seiðr), which in popular culture is usually expressed as the Old Ways.
That Custom, Seiðr, had two main emphases - public and private rites. Public Rites were festivals that blessed and protected the community. The private rites were incantations (sorcery) that created charms and curses. Female Seiðr practitioners are more widely attested, with such sorceresses being variously known as vǫlur, seiðkonur and vísendakona. There were also accounts of male practitioners, known as seiðmenn, but in practicing magic they brought a social taboo, known as ergi, on to themselves, and were sometimes persecuted as a result. In many cases, these magical practitioners would have had assistants to aid them in their rites.
Seiðr was associated with both Oðinn, who was simultaneously responsible for war, poetry and sorcery, and Freyja, a member of the Vanir, who was believed to have taught the practice to the Æsir.