Three Vowels of Power

IAO is a formula of three Greek vowels that appears pervasively in the Greek Magical Papyri of late antiquity and in Gnostic sources, where it functions as a potent name of God or of a cosmic power. Almost certainly derived from a vocalisation of the Hebrew divine name, it was taken up in the Hellenistic magical and Gnostic milieu as a name of power in its own right, one of the many sacred and often unintelligible names by which the practitioners of the papyri invoked and commanded spiritual forces. The vowels themselves were held to carry potency, and such vowel-formulas were intoned in magical practice.

The modern Western magical tradition, drawing on this ancient material, gave IAO renewed importance: it was worked into the ritual and symbolism of the Hermetic Order of the Golden Dawn and its successors, where it was elaborated into a formula of spiritual transformation, so that an ancient magical name of God acquired a fresh interpretation within later occultism.