Theurgy (Greek, theurgeia, from theos, «gods» and ergeia, «work») originally in ancient times theurgy served as a traditional religious purification ritual that was adopted by the magical wing of Platonism.
It was a process of cleansing the lower aspects of the self to establish a foundation for higher philosophical contemplation.
During the first centuries of the Common Era it developed into a distinct school and served as part of the same fusion of Platonic philosophy and popular occultism which gave birth to Hermeticism and many Gnostic traditions. The chief contributor to its formulation was Iamblichus of Chalcis (ca. 330).
The theurgists led what was nearly the last organized resistance against Christianity in the classical world. Julian, the last pagan Roman Emperor, was a staunch theurgist and a reverent student of Iamblichus’ writings, promoted a resurgence of paganism in the fourth century based heavily on theurgy for a philosophical stance, and a basis for mutual tolerance and support. Even after the political defeat of paganism, theurgists such as Proclus and Sosipatra continued its teaching and practice. However it dwindled out slowly on the edges of the Byzantine Empire but seemed to survive in outposts such as Harran until the Middle Ages.
A Christian interpretation of theurgy from Greek is «divine action»; and further interpreted it to be the inducement of a direct action of God through a human agent. It is in contrast of black magic, instead of calling on powers of forces opposed to God, demonic forces, theurgy calls on help from angels and saints who are mediators of God’s power. The teaching of Neoplatonism in regard to theurgy was that divine powers entered the soul to make the mystic, him or her, superhuman, though Plotinus himself opposed theurgists. Augustine accused them of «criminal curiosity.»
The language and various practices of theurgy were revived during the Renaissance. This revival was assisted by the spread of classical Platonism and Hermerticism. Renaissance theurgy greatly aided the occult tradition of that time and is discussed at length in such works as Agrippa’s Three Books of Occult Philosophy (1531).
Currently theurgy refers to any form of magic that encompasses the transformation of the magician, which, incidentally, was the classical aim of theurgy. However, several variants exist. There are some French esoteric Christian versions in which the word is used for focused contemplative prayer seeks practical as well as spiritual goals. In some current Pagan traditions, theurgy calls on the help of the gods in magic workings, opposed to thaumaturgy, using powers of natural substances or those of the magician. A.G.H.
Sources:
Bowker, John. ed. The Oxford Dictionary of World Religions. New York. Oxford University Press. 1997. p. 971 Byzantine Empire. <http://en.wikipedia.org/wiki/Byzantine_empire>
Greer, John Michael. The New Encyclopedia of the Occult. St. Paul, MN, Llewellyn Worldwide. pp. 483-484