Catalysts and Causes: Mechanisms of Transformation
The mechanisms prompting transformation vary across the literature, as does the degree to which narrators show an interest in them. Transformations can occur through verbal utterances, particularly curses, which are prevalent in fornaldarsögur. In these stories, princesses are frequently transformed into troll-women as part of the ‘loathly lady’ trope (see Þorsteins saga Víkingssonar, Gríms saga loðinkinna, Hjálmþérs saga and Illuga saga Gríðarfostra). These curses stipulate permanent transformation unless specific conditions are fulfilled, often involving a man’s courteous behaviour toward the transformed woman. Such narratives therefore use female transformation less to explore female embodiment and subjectivity, and more to establish the heroic credentials of the male protagonists.
Magic also plays a significant role in eliciting transformations, denoted by terms like trollskapr (witchcraft, supernatural power)1 Vǫls., ch. 5 (p. 8). and kynngi/fjǫlkynngi (magic, sorcery).2 Vǫls., chs 5, 7 (pp. 8, 9); ÞorstVík., ch. 3 (p. 390); Harð., ch. 26 (pp. 67–8); Hkr., ch. 33 (I, 271); HHv. (p. 260); Hem. (p. 40); Ldn(H), ch. 309 (p. 109). The term sjónhverfingar (sight-deception) also recurs in instances of transformation that are explicitly discredited as illusory and immaterial.3 Gylf., ch. 47 (p. 42); Eb., ch. 20 (pp. 51–2); Harð., ch. 26 (pp. 67–8). Beyond magical acts, a variety of powerful objects enable transformations: these objects can be gazed into (mirrors/glass,4 E.g., EgÁsm., ch. 15 (p. 70); SigÞǫgl., ch. 21 (p. 158). stones),5 E.g., Gibb., ch. 13 (p. 74). physically touched (shield,6 E.g., Mág. I, ch. 19 (p. 38). gloves)7 E.g., Hrólf., ch. 19 (p. 55). or worn (skin).8 E.g., Vǫls., ch. 8 (pp. 11–12); Vkv. 2 (p. 430). Transformation mechanisms are particularly varied in fornaldarsögur and riddarasögur, where narrators display a keen interest in the nonhuman agencies driving transformations. By contrast, in Íslendingasögur, transformations (which are usually depicted as sight-deceptions, see Chapter 5) are often induced through illicit magic rather than fantastical objects.
Mythological texts are generally more focused on the narrative consequences of a transformation than the specific mechanisms eliciting it. In these narratives, transformations either occur via hamr or are presented without reference to magic, suggesting that such changes are an intrinsic and uncontroversial aspect of the mythological world. While Snorra Edda does use the frame narrative in Gylfaginning to characterise the æsir’s magical abilities as sjónhverfingar (they ‘gerðu í móti honum sjónhverfingar’ – ‘prepared sight-deceptions against him [Gylfi]’),9 Gylf., ch. 2 (p. 6). this language does not appear in the mythological narratives themselves, where transformations are presented as authentic and material.10 The frame narrative of Skáldskaparmál similarly presents the æsir preparing for Ægir’s arrival ‘með sjónhverfingum’ (ch. G55, p. 1: ‘with sight-deceptions’). The sole exception is the Útgarða-Loki narrative, where transformations are revealed to be sjónhverfingar.11 Gylf., ch. 47 (p. 52). See Chapter 3. The Útgarða-Loki narrative is itself a mise-en-abyme of the frame narrative, with the deceptive transformations in the episode mirroring the illusions described in the overarching frame narrative. This parallel subtly reinforces Snorri’s euhemeristic presentation of the æsir by suggesting that all magic performed in the mythological narratives of Gylfaginning may be illusory. In the Poetic Edda, most transformations are described without employment of vocabulary involving witchcraft or trickery.12 The one exception appears in Lokasenna 23, where Óðinn’s travel in the form of a wizard is associated with practicing seiðr.
 
1      Vǫls., ch. 5 (p. 8). »
2      Vǫls., chs 5, 7 (pp. 8, 9); ÞorstVík., ch. 3 (p. 390); Harð., ch. 26 (pp. 67–8); Hkr., ch. 33 (I, 271); HHv. (p. 260); Hem. (p. 40); Ldn(H), ch. 309 (p. 109). »
3      Gylf., ch. 47 (p. 42); Eb., ch. 20 (pp. 51–2); Harð., ch. 26 (pp. 67–8). »
4      E.g., EgÁsm., ch. 15 (p. 70); SigÞǫgl., ch. 21 (p. 158). »
5      E.g., Gibb., ch. 13 (p. 74). »
6      E.g., Mág. I, ch. 19 (p. 38). »
7      E.g., Hrólf., ch. 19 (p. 55). »
8      E.g., Vǫls., ch. 8 (pp. 11–12); Vkv. 2 (p. 430). »
9      Gylf., ch. 2 (p. 6). »
10      The frame narrative of Skáldskaparmál similarly presents the æsir preparing for Ægir’s arrival ‘með sjónhverfingum’ (ch. G55, p. 1: ‘with sight-deceptions’). »
11      Gylf., ch. 47 (p. 52). See Chapter 3. »
12      The one exception appears in Lokasenna 23, where Óðinn’s travel in the form of a wizard is associated with practicing seiðr»