Our sources do not record how seiðr was practiced, so any modern book of seiðr practices is going to be the modern UPG of its author, regardless of who writes it. What we know of seiðr must be gleaned from the sources. In the Saga of Erik the Red, seiðr is accompanied by women singing songs called vard-lokkur, which we know nothing more about. Most of what we think we know of seiðr comes directly from Snorri Sturluson's euhemerized accounts of the human "Asia-men" (Aesir) as told in his historical work Heimskringla, Ynglingasaga chapters 4 and 7. Snorri describes it as a form of dark magic practiced by Odin in chapter 7, and modern scholars like Anthony Faulkes and Alison Finlay have translated the word seiðr as "black magic", justly I believe.
What Snorri says of the Vanir and seiðr in his Ynglingasaga seems to be based on his limited understanding of statements in the poem Lokasenna, which he knew, and quotes in his Prose Edda. Ynglingasaga, ch. 4, is the only source for the statement that Freyja taught seiðr to the Aesir. We have no other evidence she actually didor even practiced it herself. The idea that it is exclusively a woman's magic is based on the verse where Loki mocks Odin for practicing itand dressing as a volva while doing so. But the sources give us additional information. A skaldic verse preserved in Skaldskaparmalinforms us that "Odin worked seiðr on Rind." We have the full story in Saxo's Danish History Book 3. There Odin uses magic to seduce Rind, and after cursing her with it, posed as a female physician to gain access to her under her father's nose. Afterward, Odin is deposed for the space of 10 years for staining his godhead and upon his return banishes sorcery from his kingdom. This corresponds to the Van-As war when the Aesir were banished from Asgard for a time. Since we have examples of other men using seiðr too, Snorri's statements about it being shameful for men (as opposed to women) to practice seiðr, don't ring true. In the poetic sources, seiðr was brought to Midgard by the giantess Heid (see Voluspa 21-22, and Hyndluljod 32 and the following verses). She spread it from house to house, in the same way that Heimdall sanctified culture and spread runes as he travelled in the poem Rigsthula. Of Heid and her magic practices, Voluspa 22 tells that she was "ever the delight of evil people", or "evil women" depending on the readings in the two manuscripts. There is no indication that this is a Christian interpolation, as some suggest. Snorri does not quote or explain these verses, allowing speculation to run rampant. But the poems themselves give us further insight into the nature of seiðr.
In the Haukbók mss of Voluspa 22, seiðr is described specifically as "hug-leikinn" or "playing with minds". When Odin practiced it, he only did so after trying to court Rind in the usual way. After she refuses him 3 times, he resorted to seiðr to drive her mad, then posed as a volva to "heal" her of the spell he had himself cast. So in that instance, indeed, he "played with her mind." Posing as a female was simply to get access to her with her father present. He actually cast-the spell while posing as a male, then only appeared as a volva afterward. Snorri doesn't tell the full story of Rind, and so may not have had a poem that included it. He was likely working from manuscripts which we know circulated in his time, and not from some personal experience with paganism as people assume. His homeland Iceland was converted more than two centuries earlier, and Snorri expresses both the Christian worldview and history in his Edda, making the heathen gods foreign invaders and conquerors from the Classical world [the city of Troy, which he knew from his Roman Catholic education]. Snorri makes no mention of Heimdall travelling as Rig, or of Gullveig-Heid in his Prose Edda (despite both playing prominent roles in Voluspa, a poem he knew well; as evidence of this, Snorri makes no mention of Voluspa 1, 21, or 22) which is what has led to all the modern speculation about the nature of seiðr.
In the sources, seiðr is a form of black magic originating with the hostile giants as opposed to runic magic, called galdur, taught to Odin by the friendly giant Mimir, who was his mother Bestla's brother (see Havamal 140). In the sources, both men and women practice galdur(see the poem Grougaldur for examples; Groa's galdur are spells of protection for her son Svipdag, who married Menglad-Freyja in the poem Fjolsvinsmal. In other words, he's her husband Odr, folks! Like Freyja herself, her husband is known by many names in our lore). Men and women alike practice seiðr, and by all accounts it is a dark form of magic. What the skald Kormak, quoted in Skaldskaparmal,calls seiðr, Saxo describes as Odin cutting runes on a piece of bark and touching Rind with it; at once, she goes mad and falls sick. This conforms to Snorri’s description of seiðr in Ynglingasaga ch. 7, where he says it “brings people death, ill-luck and sickness, or he took power and wit from them and gave it to others.” In his description, Snorri also says seiðr allowed Odin “to know men’s fates and of the future”, however, prophecy is a form of magic better known as spá, which the Vanir specialize in. In Voluspa 23, the Vanir overcome the Aesir in war with vig-spá, “battle-prophecy”; and in Thrymskvida 15, Heimdall is said to foresee the future well, like all Vanir do. It is important to recognize that both spá (prophecy) and seiðr are listed as distinct magical arts taught by the giantess Heid in Voluspa 22, along with enchanting gandr (magical objects and familiars), a third magical art. Snorri seems to have conflated the first two in Ynglingasaga ch. 7, calling both forms “seiðr”. If Freyja learned seiðr, it was likely taught to her by her giantess maidservant Aurboda (who is the mother of her brother Freyr's giant-bride Gerd, according to Hyndluljod 30). In Book 7 of Saxo’s Danish History, we see that Otharus’ (Ottar-Odr’s) girl was betrayed to the giants by a maidservant of hers, whom many thought was a giant herself. There Otharus’ love-interest is called Syritha, a Latin form of the name Syr, a known byname of Freyja. He rescues her from captivity among the giants. After the burnings of Gullveig-Heidr, who spread seiðr among mankind in verses 21 and 22, Voluspa 25 asks "who blended the air with cunning, and gave Odr's girl to the jotuns?" In context, the answer must be Gullveig-Heid, whom the gods tried to burn three times, unsuccessfully. She returns each time. Gerd's mother Aurbodais one of the maidens at Menglad-Freyja's feet in Fjolsvinsmal 38. In Skirnismal, we see Freyr under some sort of spell that effects his mind, causing him great distress until he marries Gerd. Could Freyr's love-sickness be the result of seiðr, cast upon him by his sister Freyja's maidservant Aurboda?
In Volsungasaga ch. 2, we also see the giant Hrimnir's daughter (who is called Heid in Hyndluljod 32, and directly associated with practitioners of seiðr in the subsequent verses) as a maid servant of Frigg As in Fjolsvinsmal, the role of this jotun maidservant in childbirth is emphasized. In Volsungasaga, she has a clear corrupting influence on mankind, and in Fjolsvinnsmal, she is set in opposition to Eir, the physician among the goddesses, suggesting the same. There the two figures, Eir and Aurboda, may represent the two aspects of pregnancy and birth-- the wonderful, healthy side and the horrific side, in which children are deformed and/or the mother dies in the process. In Volsungasaga chapter 2, Hrimnir's daughter delivers an apple on behalf of Frigg to a barren queen. The resulting pregnancy is extended to years unnaturally, and the mother dies in hard labor. The giantess returns to marry the child when he comes of age, and the resulting marriage produces princes who are werewolves. In Fjolsvinnsmal, Eir and Aurboda are the only two recognizable names among Menglad-Freyja's attendants. These goddesses are specifically said to help women with childbirth. In Oddrunargratr 9, both Frigg and Freyja are invoked for help with childbirth. In Volsungasaga and Fjolsvinsnmal, each goddess has a hostile giantess as a maidservant who assists in this role. She is the source of actual seiðr among the gods, according to Voluspa 21-22, and the gods burn her three times. The Vanir only object to this burning, because she was now Freyr's mother-in-law. This suggests that the Van-As war was much later in the timeline than we have been led to believe, and that the Vanir and Aesir has formerly intermarried and exchanged hostages as part of a peace pact and had been living together at peace for many years, when the giantess Gullveig-Heid caused a war between them.
- Research by William P. Reaves
Author of Odin’s Wife: Mother Earth in Germanic Mythology