(RNS) — As children dress up as witches for Halloween, we are reminded that there was a time when witches were persecuted and executed by society.

For a look at this ugly period of European history, I interviewed the Rev. David Collins, a Jesuit professor of history at Georgetown University.

This interview was edited for length and clarity.

Why did you get interested in witches?

I became interested in witches because I was interested in magic more generally. Historians study medieval magic for the light it sheds on how medieval people thought the natural world functioned and how they could use, harness and take advantage of natural forces in the created world.

I had done my dissertation on saints. Miracles are a big part of that story, and medieval theologians and churchmen were very interested in figuring out the difference between miracles and magic. In some instances, it was even difficult to distinguish between people who worked miracles and practiced magic. If miracles are evidence for holiness and magic the product of magic, how in fact can you come up with a reliable way to distinguish saints from sorcerers?

After so much research on saints, I was also eager to mix things up and turned to magicians and witches, whom I work on now.

So, what is a witch?

There is not a clear definition. It depends very much on the culture and the historical period you are looking at. In the Middle Ages its was rarely something you called yourself, usually something you were accused of being.

What people today usually have in mind is a broom-piloting, pointy-hat-wearing and cackling old woman who does evil. It is also someone who was hunted and persecuted with irrational fervor in the past.

The historical witch hunt that people usually have in mind is not medieval; it is a little more recent than that. When we think of the witches who were burned or prosecuted, we are talking about something that emerges in the 15th century and lasts until the end of the 18th century.

In this period, a witch was defined as a person who made a pact with the devil. The pact was usually sealed by sexual intercourse with the devil, and witches formed a community of evildoers, gathering regularly at so-called sabbats. The pacts are what made their evil so powerful.

There has always been a notion of women who do bad things or people who use magic to harm other people. The business of a pact with the devil is unique or characteristic to Western history as opposed to the rest of the world. And the pact was at the heart of the larger social concerns that motivated the persecutions of the early modern period (1400-1800).

That is something that emerges in the late Middle Ages and starts to be prosecuted with vigor in the middle of the 15th century. The first big trials are early 15th century and the last ones are about the 1770s.

This is how their opponents described witches. Did the witches themselves think they were making a pact with the devil?

There are two schools of thought on this. One argues that this belief in witchcraft was invented by the forces who were accusing for their own purposes. The other school of thought argues that the accused genuinely believed in their witchcraft.

Clearly the witch trials were born of power plays by religious and secular forces that wanted to gain greater control over religious and civil communities. But we also have plenty of examples of people who confessed to the charges as defined. Not all can be explained by torture, although the possibility of torture is always present.

Where did the idea of a pact with the devil come from?

It really begins around 1200, among the literate and the learned, as they thought about learned magic and sorcery. Think Faust, a pact with the devil for occult knowledge and the manipulation of the natural world like alchemy.

We have necromancy manuals, which clearly come out of learned clerical milieu, in the late 14th, early 15th century. They are conjuring up the spirits of the dead in order to get their help in doing things. The necromancy manuals in the structure of the rituals and the ceremonies are mirror images of exorcisms. “If you can expel a demon from a person, perhaps you can conjure a demon.”

In addition to a desire to command hidden knowledge, there was a financial element driving this “research.” They were doing this for money. Who wouldn’t want their treasuries enhanced by the alchemist’s newly created gold bullion. And all kinds of powerful people were interested in horoscopes — princes, popes, all of them — how else would you know the propitious days to sign contracts, make treaties, marry off your children, etc.

Around 1400, the concern about the help from the devil to get at deeper sources of mystical knowledge, esoteric knowledge, gets fused with the popular magic that is practiced in villages.

Part of the social tragedy is that the number of prosecutions and executions for these elite figures is minimal. There is a certain kind of person that becomes pinched between a bizarre fixation with the power of the demon in the world coming from above, and social bitterness and prejudice that is coming from below. And boom, the witches are pinched in-between the two.

Was magic in and of itself seen as evil?

Historically, there emerged the idea of occult forces that can be used for good ends. The scholastic theologian of the 15th or 16th centuries would say, “If you are manipulating the powers of the natural world in a way that is natural and has good ends, well then it is really not even magic.” These occult forces in natural objects are there to be taken fullest advantage of.

The love potion made for an interesting case study in schools. “Can you use a love potion on your spouse who has fallen out of love with you?” There are two issues for the young students to debate. One has to do with whether the making of the substance was licit and natural. The other has to do with free will: “Is the use of a love potion depriving the other party of their freedom, regrettable as it is that a spouse falls out of love?”

But there were others who would say that a love potion is a good thing because marriage can be difficult sometimes. The embers cool a little bit, and it would be good for the embers to be relit. So, they would go back and forth on that.

What kind of evidence would be used in a witch trial?

It is fairly arbitrary. Remember the scene in “Monty Python and the Holy Grail,” about the duck. I hate using contemporary popular art to explain history, but I think that captures the problem, actually.

People believed that there were people who were witches who had made pacts with the devil, and they believed that they did genuine harm. If a town council or the consultors to the archbishop are getting a consistent set of problems tossed in their lap and they start putting two and two together, “Well, it could be witches.”

Then, “Why don’t we have a trial?” Then you start heading down in a particular direction, you are looking for them, and you find what you are looking for.

The first really important book against the witchcraft trials was "Cautio Criminalis" by Friedrich Spee in 1631. He is a Jesuit and a confessor to witches who have been condemned. He wrote a treatise arguing for the stopping of the trials on the grounds that there was not an adequate standard of evidence. He was not disputing that there is such a thing as witches.

The most famous guide to witch trials, although not the most commonly used at the time, is “Malleus Maleficarum” (the Hammer of Witches) by Heinrich Kramer, who wrote the book in the 1480s after he failed to get convictions at a particular set of trials in Innsbruck. About a third is a misogynist screed, ideas cobbled together from antiquity to the contemporary moment; a third is on how do you find a witch; and a third is on procedure, how to do a trial.

How many witches were executed?

From 1450 until 1750 there are probably 100,000 trials maximum. In the 1970s, the number bandied about was 9 million, but we are now down to between 100,000 and 70,000 trials. These were largely civil trials, rather than church trials. There were 30,000 to 50,000 executions over that 300-year period. Recent scholarship is supporting the lower numbers.

It is also important to realize that there was not a sustained, consistent rate of prosecutions between 1450 and 1750. It breaks out in particular places and particular times. Trials will go on for a couple years and then disappear. Or it will last for a year and then suddenly 50 years later it will appear again.

There is a high execution rate, but there is an even higher conviction rate. There were more convictions than executions. There was the possibility of penalties short of execution. So, if you recanted your pact with the devil, if the evidence wasn’t quite enough for a full conviction for witchcraft, well then there were lesser penalties.

What makes it break out?

Once the elite idea of sorcery and the popular idea of witchcraft join, the key player in the emergence of the larger trials tends to be the prominent person in a small town. Often what seems to be the case is that bad things were happening and someone needed to be blamed.

In the absence of other explanation, maleficent magic served their purposes: Blame whatever needs to be explained on someone who for some other reason was socially disconnected or despised or mistrusted within the community.

There are problems of long standing. And suddenly in a moment it is, “Ah, the solution to these problems of long standing is to start hunting down the witches.”

What impact did the Reformation have on witch trials?

When the Reformation starts there is a dip, a pause. People are distracted. But by the 1550s-1560s, the number of prosecutions and executions rises again, especially in Germany. Seventy percent of the trials and executions were in Germany. Something like 90 to 95 percent of people executed for witchcraft spoke a dialect of German.

Also, after the Reformation, it is the secular courts that try witches. And this is when it becomes really brutal. The 1560 to 1660 period, which is when the most brutal accusations are, it is secular courts, with the encouragement of ecclesiastical officials, that are driving it.

There also seems to be a bit of an association with a religious concern about reforming Christian society. The ecclesiastical figures who are concerned about pacts with the devil are also talking about reform of the church. They are looking at Christendom and saying, “We have been working at this for 1500 years and still we don’t have the kingdom of God. Why is that? It is because too many people are making pacts with the devil.”

Why were there more witch trials in Germany than in other parts of Europe?

Think back to the importance of local players in getting someone prosecuted for witchcraft. If you have a highly centralized legal system, it forces multiple layers of review. In France, for example, you have a small number of executions, and they peter out earlier on. After an initial enthusiasm, it stops. Why? Because of the court system.

In France, a centralized judiciary in Paris takes a key role in supervising trials. A small village outside of Toulouse might convict 20 witches at once, but these convictions work their way to Paris, and many of them that eventually get there are overturned.

What do we not have in the Holy Roman Empire? We don’t have a strong central government. We have the emperor but you have these principalities, upwards to 300 of these principalities, each is responsible for its own execution of justice. Precisely these layers of supervision are missing and this is one of the reasons they last as long as they do in Germany.

What was the most centralized court system in Europe in the 15th, 16th and 17th centuries? The inquisition. So, in places where the organized inquisitions, the Roman and Spanish, were the strongest, you have almost no witch trials. Spain and Ireland, you have almost none. Italy, very few. Again, where you had the less centralized court systems, then you have more and more.

What lesson do the witch trials have for us today?

The human tendencies that lead elite and regular folk alike to conspire to prosecute and persecute in the early modern period are no less with us today. Our creativity at coming up with scapegoats — at inventing ideologies to explain things that open reason and real experience can't, at voicing our frustrations at the limits of our accomplishments with violence, at justifying this violence with appeal to raison d'etat and purity of belief — knows no bounds.

Interestingly, it was bureaucracy that started this particular calamity, and bureaucracy that ended it. Alertness to human irrationality and some self-doubt, especially when it comes to the ways we restrict, punish and scapegoat others, are certainly challenges from the witch hunts. But then, there's not much in the last century to suggest we'll ever learn.

(The views expressed in this opinion piece do not necessarily reflect those of Religion News Service.)