This was a particularly interesting chapter in the compilation book published by the Folio Society, because I had just recently read ‘The Sun King’ by Nancy Mitford on Louis XIV and this event and its sequel figured prominently. The bulk of the chapter was written by Alexandre Dumas in his book “Celebrated Crimes”.
The crime itself was a pretty spectacular one. The Marquise, having a spendthrift husband needed to increase her income. Since you can’t go work at the 7-11 if you are in the aristocracy, you have to fall back on inheritance. Sadly, her father wasn’t dying at the moment.
At this time there was a supply of poison experts around, but the Marquise wasn’t going to take their advice on faith. So she went to the city hospitals and brought poisoned treats to some of the poor patients and later inquired as to how they had passed away.
With the right poison in hand, she dosed her father and ‘nursed’ his way into a coffin. To her embarassment, however, she didn’t inherit much at all! So she had to also poison her brothers, and attempted to do in a sister as well.
Eventually, her poison supplier gave up her name to the authorities and she came under investigation. She had written a confession of her crimes and kept it in a box, which was found. So the trial itself was something of an anti-climax.
She was arrested, questioned, tortured after the conviction to smoke out any accomplices, and executed. Her body was burned outside of Notre Dame in Paris. There was a current joke that breathing in her ashes put an itch for poisoning in the air in the city, and in fact there was a rash of poisonings and rumors of poisonings leading up to “The Affair of the Poisons” in which members of the court of Louis XIV were implicated , supposedly even his mistress.