At the beginning of the nineteenth century, there was a cliché circulating according to which magicians were also experts in astrology. Some were reported to have used music to summon astrological powers through the planets, based on a Pythagorean tradition, and the vowels that we find in the Graeco-Egyptian magical papyri were said to record the musical scale. Yet this “tradition” is primarily a matter of historiography and does not match with the practices and dynamics of cultural accommodation. A detailed analysis of the corpus reveals that the astrological interpretation does not derive from a Greek philosophical tradition but is rather a specific and targeted invention. It is therefore necessary to look at this practice from an emic perspective: vowels are occasionally linked with planets but they essentially stand for the power of breathing (πνεῦμα) and its capacity to produce sounds.