“The tension between skepticism and credulity in the seventeenth century produced a new phenomenon, the black mass, a strange combination of disbelief in Christianity and belief in the Christian Devil. . . .

Several elements distinguish such phenomena from witchcraft: first, the focus was more exclusively on sex; second, the obscene rites were presided over by a priest. . . .

Such fantasies plumbed the lowest depths in the black masses of the 1670s. A brisk trade in fortunetelling, aphrodisiacs, and poisons was uncovered by the Paris police in 1678. As the scope of the crimes among reputable families and nobility was revealed, a special court was established to deal with them. The investigations brought to light magic and black masses as well as drugs and poisons. The affair got out of hand as people began to see how they might use lurid accusations against their enemies for their own political and economic advantage. In 1680 a number of priests were indicted for saying mass on the bodies of naked women at the center of a ring of black candles, of leading the congregation in sexual intercourse, of ritual copulation on the altar, of sacrificing animals, of murdering children and using their blood in the preparation of aphrodisiacs, of desecrating the Eucharist, of using the chalice to mix children’s blood with sexual fluids, of invoking the Devil, and of making a written pact with him. . . . The king terminated the proceedings of 1682, issuing an edict eliminating prosecution for witchcraft. The black mass, a product of the cynical, skeptical, yet credulous seventeenth century, was not revived until the late nineteenth century.”

—Jeffrey Burton Russell, from The Prince of Darkness: Radical Evil and the Power of Good in History, 1988.