This date’s story is amply but succinctly conveyed by the public-domain entry in the 19th century tome Biography, or Third Division of the “English Encyclopedia”.
(Paragraph breaks have been added for readability.)
Brinvilliers, Marie Marguerite, Marquise de (English Wikipedia entry | French) who obtained infamy as a poisoner in the time of Louis XIV, was a daughter of the Dreux d’Aubrai, a lieutenant civil, or judge having a certain limited jurisdiction, at whose hands she received a careful education.
In 1651, whilst still very young, she became the wife of the Marquis de Brinvilliers, with whom she resided at her father’s house, in Paris. Her husband, who was the colonel of the Regiment de Normandie, entertained at his house a young officer of cavalry of the Regiment de Tracy, named Gaudin de Sainte-Croix, a native of Montauban, and the illegitimate member of an illustrious family. He was unprincipled enough to encourage the unlawful passion which the marchioness conceived for him; and her father, in consequence, procured in 1663 a lettre de cachet against Sainte-Croix, who underwent a year’s incarceration in the Bastille.
During his confinement he learned from a fellow-prisoner, an Italian named Exili, the art of preparing subtle poisons; a secret which, upon his enlargement, he communicated to his mistress, who determined to poison her father and the other members of her family. Having first wantonly essayed her art upon the patients of the Hotel-Dieu, she proceeded, with the aid of a servant named Jean Amelin, or La Chaussee, to take the lives of her father, her two brothers, and her sister.
This feat she accomplished gradually between the years 1666 and 1670. More than once she poisoned her husband; but Sainte-Croix, whose prudence shrank from the obligation of marrying the terrible widow, each time preserved the life of the Marquis by the administration of an antidote.
Sainte-Croix died suddenly in July, 1672, in the act, it is said, of compounding a subtle poison, against the effects of which he was left unprotected by the accidental fracture of a glass mask which he wore as a defence against the fumes of his deadly drugs.*
As no relative came forward to claim his property, it was taken possession of by the public authorities, who, instead of complying with the written instructions of Sainte-Croix,** dated May 25th, 1672, that a particular casket should be delivered to Madame de Brinvilliers, examined it, together with above thirty letters which he had received from her. There was also found a promise on her part to pay Sainte-Croix a sum of 30,000 libres, bearing the date of June 20th, 1670, eight days after the poisoning of the “lieutenant civil,” her father. The casket proved to be full of packets of various poisons, to each of which was affixed a label indicating the peculiar effects it was calculated to produce.
The Marchioness, fatally compromised by these and other circumstances, sought safety in flight, repairing first to England, then to Germany, and finally to Liege, where she was apprehended.
Being taken to Paris, she denied her guilt; but after her condemnation made a confession, in which, and in a kind of autobiography, she charged herself with more and greater horrors than had seemed possible to rumour or suspicion.
The Marquise de Brinvilliers, shortly before her execution, by Charles LeBrun
She was executed at seven o’clock on the evening of the 16th of July, 1676, being first beheaded and afterwards burnt. As her application and use of poison, which went by the name of poudre de succession, seemed to be growing prevalent, Louis XIV instituted a special court for the investigation and punishment of this species of crime.
This tale, uniting the attractions of bodice-ripper, true crime, and costume drama, has been adapted to stage and literature numerous times.
Alexandre Dumas pere, a true aficionado of historical crime and scandal, turned it into a much lengthier piece, from which we morbidly excerpt his description of the water torture the criminal endured prior to beheading — beginning with the sentence of the court.
“That by the finding of the court, d’Aubray de Brinvilliers is convicted of causing the death by poison of Maitre Dreux d’Aubray, her father, and of the two Maitres d’Aubray, her brothers, one a civil lieutenant, the other a councillor to the Parliament, also of attempting the life of Therese d’Aubray, her sister; in punishment whereof the court has condemned and does condemn the said d’Aubray de Brinvilliers to make the rightful atonement before the great gate of the church of Paris, whither she shall be conveyed in a tumbril, barefoot, a rope on her neck, holding in her hands a burning torch two pounds in weight; and there on her knees she shall say and declare that maliciously, with desire for revenge and seeking their goods, she did poison her father, cause to be poisoned her two brothers, and attempt the life of her sister, whereof she doth repent, asking pardon of God, of the king, and of the judges; and when this is done, she shall be conveyed and carried in the same tumbril to the Place de Greve of this town, there to have her head cut off on a scaffold to be set up for the purpose at that place; afterwards her body to be burnt and the ashes scattered; and first she is to be subjected to the question ordinary and extraordinary, that she may reveal the names of her accomplices. She is declared to be deprived of all successions from her said father, brothers, and sister, from the date of the several crimes; and all her goods are confiscated to the proper persons; and the sum of 4000 livres shall be paid out of her estate to the king, and 400 livres to the Church for prayers to be said on behalf of the poisoned persons; and all the costs shall be paid, including those of Amelin called Lachaussee. In Parliament, 16th July 1676.
The marquise heard her sentence without showing any sign of fear or weakness. When it was finished, she said to the registrar, “Will you, sir, be so kind as to read it again? I had not expected the tumbril, and I was so much struck by that that I lost the thread of what followed.”
The registrar read the sentence again. From that moment she was the property of the executioner, who approached her. She knew him by the cord he held in his hands, and extended her own, looking him over coolly from head to foot without a word. The judges then filed out, disclosing as they did so the various apparatus of the question. The marquise firmly gazed upon the racks and ghastly rings, on which so many had been stretched crying and screaming. She noticed the three buckets of water prepared for her, and turned to the registrar — for she would not address the executioner — saying, with a smile, “No doubt all this water is to drown me in? I hope you don’t suppose that a person of my size could swallow it all.” The executioner said not a word, but began taking off her cloak and all her other garments, until she was completely naked. He then led her up to the wall and made her sit on the rack of the ordinary question, two feet from the ground. There she was again asked to give the names of her accomplices, the composition of the poison and its antidote; but she made the same reply as to the doctor [namely, that she had no accomplices besides Sainte-Croix and did not know how to make the poison or its antidote], only adding, “If you do not believe me, you have my body in your hands, and you can torture me.”
The registrar signed to the executioner to do his duty. He first fastened the feet of the marquise to two rings close together fixed to a board; then making her lie down, he fastened her wrists to two other rings in the wall, distant about three feet from each other. The head was at the same height as the feet, and the body, held up on a trestle, described a half-curve, as though lying over a wheel. To increase the stretch of the limbs, the man gave two turns to a crank, which pushed the feet, at first about twelve inches from the rings, to a distance of six inches. And here we may leave our narrative to reproduce the official report.
“On the small trestle, while she was being stretched, she said several times, ‘My God! you are killing me! And I only spoke the truth.’
“The water was given: she turned and twisted, saying, ‘You are killing me!’
“The water was again given.
“Admonished to name her accomplices, she said there was only one man, who had asked her for poison to get rid of his wife, but he was dead.
“The water was given; she moved a little, but would not say anything.
“Admonished to say why, if she had no accomplice, she had written from the Conciergerie to Penautier, begging him to do all he could for her, and to remember that his interests in this matter were the same as her own, she said that she never knew Penautier had had any understanding with Sainte-Croix about the poisons, and it would be a lie to say otherwise; but when a paper was found in Sainte-Croix’s box that concerned Penautier, she remembered how often she had seen him at the house, and thought it possible that the friendship might have included some business about the poisons; that, being in doubt on the point, she risked writing a letter as though she were sure, for by doing so she was not prejudicing her own case; for either Penautier was an accomplice of Sainte-Croix or he was not. If he was, he would suppose the marquise knew enough to accuse him, and would accordingly do his best to save her; if he was not, the letter was a letter wasted, and that was all.
“The water was again given; she turned and twisted much, but said that on this subject she had said all she possibly could; if she said anything else, it would be untrue.”
* According to Anne Somerset in The Affair of the Poisons: Murder, Infanticide, and Satanism at the Court of Louis XIV, this story of Sainte-Croix’s death by accidental exposure to his own toxins is “a myth” that developed in view of subsequent events.
“In fact,” writes Somerset, “his end was far more prosaic. He died after a long illness, having received the last rites and performed his final devotions with terrible piety.”
** Because Sainte-Croix died in debt, and his possessions were inventoried for his creditors.