“This is the single greatest witch hunt of a politician in American history!” President Donald Trump tweeted Thursday, apparently responding to the Justice Department appointing a special counsel to investigate his and his associates' potential ties to Russia.

That got us thinking about the real Salem Witch Trials, which are commonly cited as the source of the phrase “witch hunt."

These trials happened in Salem, Massachusetts, during the winter and spring of 1692-1693. When it was all over, 141 suspects, both men and women, were tried as witches. Nineteen were executed by hanging. One was pressed to death by heavy stones. Several more perished in harsh prisons.

"As a country we have a long history of witch hunting, especially in the colonial period," says Jason Coy, a professor of history at the College of Charleston who is an expert on witch hunts.

Coy says that the way that Trump used the phrase—alleging a politically motivated campaign of persecution against an innocent person—took off after the 1950s McCarthy hearings on suspected Communists and after the success of Arthur Miller's 1953 play The Crucible, written as an allegory for that period.

In fact, the congressman who represents Salem now, Seth Moulton (D), tweeted a pithy rebuttal to Trump Thursday.

Here’s what we know about the original witch hunt:

1. There were complex political, religious, and racial issues under the crisis.

A lot was changing in colonial America at the time. Salem was divided into a prosperous town—second only to Boston—and a farming village. The two entities often bickered over resources, politics, and religion. Further complicating things, the villagers split into factions over whether to declare independence from the town.

In 1689 the villagers won the right to establish their own church. They chose Reverend Samuel Parris, a former merchant, as their minister. His rigid ways and demands for compensation—including personal title to the village parsonage—increased the friction. Many villagers vowed to drive Parris out, and they stopped contributing to his salary in October 1691.

During this tense time, Parris’s nine-year-old daughter, Betty, and her cousin Abigail Williams delighted in the mesmerizing tales spun by Tituba, a slave from Barbados.

So a number of elements were in place for a powder keg…

2. Strange behavior at the time had alarmed Salem.

In February 1692, young Betty Parris began having “fitts” that defied all explanation at the time. So did Abigail Williams and the girls’ friend Ann Putnam. Doctors and ministers watched in horror as the girls contorted themselves, cowered under chairs, and shouted nonsense.

With only rudimentary knowledge of biology, medicine, or psychology, the experts of the day concluded the girls must have been bewitched. They bullied the children until they began pointing figures at misfit women around them. Tituba was named as a witch, as was a disheveled beggar named Sarah Good and the elderly Sarah Osburn.

3. Torture led to bizarre confessions.

After being harshly beaten, Tituba began confessing and pointing her fingers even more.

“The devil came to me and bid me serve him,” she reportedly said in March 1692.

Villagers sat spellbound as Tituba spoke of black dogs, red cats, yellow birds, and a white-haired man who bade her sign the devil’s book. There were several undiscovered witches, she said, and they yearned to destroy the Puritans.

Ferreting these supposed witches out became a fever that took over the community and spilled into the surrounding region.

4. Bodies mounted.

As investigators went door to door, terrified residents pointed their fingers at still more supposed witches. Bizarre testimony and hearsay piled up. The accused were tortured and made to stand trial in hasty proceedings before a special court set up for the purpose.

Nineteen convicted “witches” were soon hanged at Gallows Hill. Defendant Giles Cory was tortured to death while refusing to enter a plea at his trial. Five others, including an infant, died in prison.

5. Some people condemned the trials… until they finally were stopped.

On October 3, 1692, the Reverend Increase Mather, president of Harvard College and father of famed preacher Cotton Mather, denounced the use of flimsy evidence and reliance on unprovable supernatural claims.

“It were better that ten suspected witches should escape than one innocent person should be condemned,” he said.

Governor William Phips grew disgusted when his own wife was eventually mentioned by the afflicted girls. Determined to quell the madness, he suspended the special court and replaced it with a new Superior Court of Judicature—which disallowed so-called spectral evidence. That court condemned only 3 of 56 defendants. Phips pardoned them along with five others awaiting execution.