Georg Luck writes in Arcana Mundi, 2nd Edition, p. 93:
The oldest Greek text in which a magical operation is mentioned forms part of Homer’s Odyssey. In this episode the hero confronts a sorceress, Circe, on her own territory. Her power is established when she transforms some of Odysseus’ companions into swine. She accomplishes this by mixing a magical drug into the special cheese mixture that she serves them and by touching them with her magic wand. Here we see the typical modus operandi of the witch (no chant or formula is mentioned, just a direct order), but unlike later witches, Circe is beautiful. This leads one to suspect that in mythological terms she is not really a witch, but a minor goddess, a survivor from an earlier generation of gods, removed—like Kronos—to a distant island and of no great concern to anyone, except, of course, if one enters her territory.