Aquinas, Thomas

Thomas Aquinas, St. (1226–1274) A Dominican and one of the greatest theologians of the Christian church, Thomas Aquinas had a profound effect on the witchhunts of the Inquisition. His revolutionary philosophy was cited by Demonologists and inquisitors for centuries as a basis for their persecutions.

Born at his family’s castle near Roccasecca, Italy, Aquinas was educated by the Benedictines at monte Cassino. He studied liberal arts at the University of Naples and then entered the Dominican order. He was sent to Paris and Cologne for training. In Cologne he met the famous alchemist, Albertus Magnus, and became his pupil in 1244, gaining a great deal of knowledge about alchemy. He is said to have performed magical feats, but these are legends.

In 1252 Aquinas returned to Paris to the Dominican St. James Convent. In 1256 he was appointed professor of theology at the University of Paris. In 1259 he traveled to Italy, where he spent nine years teaching, writing and lecturing at the papal court. He was recalled to Paris in 1268, then back to Italy in 1272. In 1274 Pope Gregory x appointed him consultant to the Council of Lyons, but Aquinas died en route, on February 7, at the Benedictine monastery of Fossanova.

During his career, Aquinas produced voluminous works that revolutionized Christian theology, most notably Summa Contra Gentiles and Summa Theologica. His philosophy had a major impact on the church’s view of witchcraft and on the transformation of sorcery into the heresy of witchcraft: heresy, even if the product of ignorance, was a sin because ignorance is the product of criminal negligence. Aquinas also stated that the practice of Magic was not virtuous and was practiced by “men of evil life.”

He believed in the Devil as a tangible person with the senses of man. While he did not believe in formal pacts with the Devil, he did believe in implicit pacts (see Devil’s Pact). A heretic, just by virtue of being a heretic, could be assumed to have somehow given himself over to the Devil, whether or not the thought had even crossed his mind. He also believed in transvection, metamorphosis, storm raising and ligatures (see Aiguillette). He was among the clerics and Demonologists who refuted the Canon Episcopi, which attributed such phenomena to delusion.

Demons, Aquinas said, do assail man and do so with the explicit permission of God. Demons and the Devil tempt man with pseudomiracles and are responsible for all sin and sexual impotence. Witchcraft, he declared, is permanent in the world, not to be remedied by more witchcraft, but only by the cessation of sin and sometimes by exorcisms performed by the church (see Exorcism).

See also :  Malleus maleficarum.


  • Kors, Alan C., and Edward Peters. Witchcraft in Europe, A Documentary History 1100–1700. Philadelphia: University of Pennsylvania Press, 1972.
  • Russell, Jeffrey Burton. Witchcraft in the Middle Ages. Ithaca and London: Cornell University Press, 1972.


The Encyclopedia of Witches, Witchcraft and Wicca – written by Rosemary Ellen Guiley – Copyright © 1989, 1999, 2008 by Visionary Living, Inc.