Taxil was an atheist who had been accused earlier of libel on account of a book he had written called The Secret Loves of Pius IX. On April 20, 1884, Pope Leo XIII published an encyclical that divided the human race into "two diverse and adverse classes, the kingdom of God on earth --- namely, the true church of Jesus Christ --- and the realm of Satan," whose headquarters were said to be in the Freemason's lodges. After this encyclical, Taxil underwent a public, feigned conversion to Roman Catholicism, and announced his intention of repairing the damage he had done to the true faith.
The first book produced by Taxil after his conversion was a four-volume history of Freemasonry, which contained fictitious eyewitness verifications of their participation in Satanism. With a collaborator who published as "Dr. Karl Hacks," Taxil wrote another book called the Devil in the Nineteenth Century, which introduced a new character "Diana Vaughan," a supposed descendant of the Rosicrucian alchemist Thomas Vaughan. The book contained many implausible tales about her encounters with incarnate demons, one of whom was supposed to have written prophecies on her back with its tail, and another played the piano in the shape of a crocodile.
She was involved in Satanic freemasonry, but was redeemed when one day she professed admiration for Joan of Arc, at whose name the demons were put to flight. As Diana Vaughan, Taxil published a book called Eucharistic Novena, a collection of prayers which were praised by the Pope.
On April 19, 1897, Taxil called a press conference at which he announced he would introduce Diana Vaughan to the press. He announced that he had forged the letter, and that all of his other revelations about the Freemasons were fictitious. He thanked the clergy for their assistance in giving publicity to his wild claims. The hoax material is still used to slander Freemasons to this day. Chick Publications publishes such a tract called The Curse of Baphomet.