THEURGY (from the Greek theourgia) means literally something like "actuating the divine" and refers to actions that induce or bring about the presence of a divine or supernatural being, whether in an artifact or a person. It was a practice closely related to magic—not least in its ritual use of material things, sacrifices, and verbal formulas to effect the believer's fellowship with the god, demon, or departed spirit. It is distinguished from ordinary magical practice less by its techniques than by its aim, which was religious (union with the divine) rather than secular. Use of the term theourgia—as well as of the related theourgos, referring to a practitioner of the art—arose in the second century CE in Hellenistic circles closely associated with the birth of Neoplatonism. The practice was commended and followed, in the third and later centuries, by certain Neoplatonist philosophers and their disciples...