Friedrich Spee (Friedrich Spee von Langenfeld) (Kaiserswerth, February 25, 1591 - Trier, August 7, 1635) was a German Jesuit and poet, most noted as an opponent of trials for witchcraft. Spee was the first person in his time who spoke strongly and with arguments against torture in general. He may be considered the first who ever gave good arguments why torture is not a way of obtaining truth from someone undergoing painful questioning. The often cited name "Friedrich von Spee" is wrong.

He was born at Kaiserswerth on the Rhine. On finishing his early education at Cologne, he entered the Society of Jesus in 1610, and, after prolonged studies and activity as a teacher at Trier, Fulda, Würzburg, Speyer, Worms and Mainz, was ordained priest in 1622. He became professor at the University of Paderborn in 1624; from 1626 he taught at Speyer, Wesel, Trier and Cologne, and was preacher at Paderborn, Cologne and Hildesheim.

He said "Often I have thought that the only reason we are all not wizards is due to the fact we have not all been tortured" (by Holly from "The Book of Spells" written by "Nicola de Pulford").

An attempt to assassinate Spee was made at Peine in 1629. He resumed his activity as professor and priest at Paderborn and later at Cologne, and in 1633 moved to Trier. During the storming of Trier by the imperial forces in March 1635, he distinguished himself in the care of the suffering, and died soon afterwards from the results of an infection contracted in a hospital.

His literary activity belongs to the last years of his life, the details of which are little known. Two of his works were not published until after his death: Goldenes Tugendbuch (Golden Book of Virtues), a book of devotion highly prized by Leibniz, and the Trutznachtigall, a collection of fifty to sixty sacred songs, which take a prominent place among religious lyrics of the seventeenth century, and have been in recent times repeatedly printed and revised. But the assumption that the author in this work applied the metrical principle independent of Opitz, is at least doubtful.

His principal work, which won him a wide reputation, is the Cautio Criminalis, written in Latin. The title means Precautions for Prosecutors. It is an arraignment of trial for witchcraft, based on his own experiences in Westphalia. The traditional assumption is that he acted for a long time as "witch confessor" in Würzburg since he seems to have knowledge of what could be considered the private thoughts of the condemned. The work was printed in 1631 at Rinteln without Spee's name or permission. He does not advocate the immediate abolition of trials for witchcraft, but describes with sarcasm the abuses in the prevailing legal proceedings, particularly the use of the rack. He demands measures of reform, such as a new German imperial law on the subject, liability to damages on the part of the judges, etc. If these had been carried out, they would have quickly put an end to the persecution of witches.

Nevertheless, the Cautio Criminalis brought about the abolition of witch burning in a number of places, especially at Mainz, and led the way to its gradual suppression. The moral impression created by the publication was very great. Even in the seventeenth century a number of new editions and German translations appeared. Among the members of Spee's Jesuit order his treatise found a favourable reception. A memorable observation in the book suggests that Germany and England must have more witches and devils than Spain and Italy since there are so many more stake burnings in the former. This may have been a not so subtle criticism of Protestant reform Europe which he believed was guilty of even greater abuses than the Catholic countries. The book is still in print.

Cautio Criminalis contains 52 questions which Spee attempts to answer. Amongst his more notable conclusions are:

• (17) That alleged witches should be allowed a lawyer and a legal defense: the enormity of the crime making this right even more important than normal.
• (20) That there is real danger innocents will confess under torture simply to stop the pain.
• (25) That condemning alleged witches for not confessing under torture is absurd. Spee opposed the notion that such silence was itself evidence of sorcery, as this made everyone guilty.
• (27) That torture does not produce truth, since those who wish to stop their own suffering can stop it with either the truth or with lies.
• (44) That denunciations of accomplices by tortured "witches" were of little value: either the tortured person was innocent, in which case she had no accomplices, or she was really in league with the Devil, in which case her denunciations cannot be trusted either.

Spee was particularly concerned about cases where a person was tortured and forced to denounce accomplices, who were then tortured and forced to denounce more accomplices, until everyone was under suspicion:

Many people who incite the Inquisition so vehemently against sorcerers in their towns and villages are not at all aware and do not notice or foresee that once they have begun to clamor for torture, every person tortured must denounce several more. The trials will continue, so eventually the denunciations will inevitably reach them and their families, since, as I warned above, no end will be found until everyone has been burned. (question 15)

Spee was not, however, a skeptic regarding the existence of witches, and opened his work with a declaration that witches are real. However, he was concerned with the fact that innocent people were being killed alongside real witches, as he thought. He argued (question 13) that the Parable of the Weeds in Matthew 13:24-30 meant that some of the guilty must be allowed freedom, so that the innocent are not condemned either.