This essay traces the journey of “theurgy” from its original, pagan associations with the Chaldean Oracles in the second century, to the Christian mystical theology of “Pseudo”-Dionysius the Areopagite in the early sixth century. The essay begins by inquiring into the theory and practice of theurgy as expressed in the fragmentary Oracles, and argues that the surviving sources do not permit us to draw firm conclusions. The essay then moves quickly over the Neoplatonic reception of theurgy, from Plotinus to Porphyry to Iamblichus. Iamblichus’ theory of theurgy is especially significant for the subsequent Christian reception. The essay ends by examining the use of the term “theurgy” in the Corpus Dionysiacum, and argues that while the author inherits the form of Iamblichean theurgy, he freights it with new content by figuring the Incarnation of Christ as the preeminent theurgy or “work of God.”