The Poison Plot That Shook Paris: The Execution of Madame Marie de Brinvilliers

Marie Madeleine Marguerite d’Aubray was born into the Parisian elite in the 1600s. She was raised with wealth, status, and connections. But what followed was anything but quiet. Her name became linked to whispered deaths, secret vials, and a final execution that left crowds stunned.

This is the story of a woman pushed to the edges of a rigid society, trapped in a loveless marriage, and swept up in a dangerous love affair. Over time, she crossed a line. Then another. And by the end, people weren’t just shocked by what she’d done, but terrified of what she represented.

Her crimes helped trigger one of the most paranoid chapters in Louis XIV’s reign. This is the real story of the Marquise de Brinvilliers. And it doesn’t flinch.

Born into Privilege: The Early Life of Marie Madeleine

Marie Madeleine Marguerite d’Aubray was born in 1630 into one of those Parisian families that never had to worry about money or reputation. Her father, Antoine Dreux d’Aubray, was a high-ranking official who served as Lieutenant Civil of Paris. That role made him one of the most powerful men in the city. Her mother came from the de Saint Rémy family, which only added to the family’s status. From the outside, it looked like the perfect setup.

She was the only daughter in a house full of brothers. Her early education likely came from a convent, which was typical for upper-class girls at the time. They were taught the kind of things that would make them good wives, such as reading, religion, a bit of music, and obedience. However, there’s no indication that Marie Madeleine was especially meek. 

Even in her youth, she was known to be clever and sharp, someone who didn’t just sit quietly and do as she was told. As she grew older, it became clear Marie Madeleine wasn’t going to settle into the role society had picked out for her. Not without a fight.

Marriage Without Love: The Marquise and the Military Man

At 21, Marie Madeleine was married off to Antoine Gobelin, Marquis de Brinvilliers. He was from a powerful family tied to the Gobelin tapestry works, and on paper, the match looked respectable. But the marriage was cold from the beginning. Antoine was more interested in cards and the company of other women than in his wife. He drank, gambled, and burned through money faster than he could earn it.

Their life together quickly became unstable. They both enjoyed numerous affairs, and his debts accumulated, forcing him to leave Paris altogether, where he escaped creditors and took a military post elsewhere. Marie Madeleine was left behind in the capital with no real companion, no husband at home, and a reputation to uphold. With her marriage quietly falling apart, she returned to her father’s household.

There, she played the part of the dutiful daughter, attending church, volunteering for charity work, and showing deference to her powerful father. Behind closed doors, though, she was still reeling from the emotional mess her marriage had become. 

When she met Michel Godin de Sainte-Croix, charming, ambitious, and far more interested in her than her absent husband ever was, something snapped into place. The affair began quickly. It was intense. And it was the start of everything that followed.

Dangerous Liaisons: Enter Godin de Sainte-Croix

Michel Godin de Sainte-Croix was everything her husband wasn’t. He was educated, smooth-talking, and connected to the court through his position as an officer in the Maison du Roi. When he met Marie Madeleine in the mid-1660s, she was already emotionally cut loose. Her marriage was a formality. 

Her husband was long gone. She was living under her father’s roof again, but playing a double game: a devoted daughter on the surface, a secret lover behind the scenes.

The affair with Sainte-Croix was no passing indulgence. It became central to her life. The two met often, exchanged letters, and confided everything in each other. But when her father found out, he was furious.

 Antoine d’Aubray considered Sainte-Croix beneath his daughter. Worse, he feared the affair could damage the family’s reputation. So he used his power to have Sainte-Croix locked up in the Bastille using a lettre de cachet, a tool the powerful used to remove people without trial quietly.

That decision changed everything. While locked up, Sainte-Croix reportedly shared a cell with an Italian alchemist and poisoner. He learned about slow-acting toxins, how to mix them, how to dose them, and how to make the deaths look natural. 

When he was released after a year, he didn’t just return to Marie Madeleine. He brought poison with him. Together, they crossed into darker territory. What started as passion was now entangled with planning, secrecy, and a growing appetite for control.

The Family Poisonings Begin

When Sainte-Croix returned from the Bastille, he came back with more than just bitterness. While imprisoned, he had learned how to mix poisons. It didn’t take long for him and Marie to start using that knowledge. She began by experimenting at the Hôtel-Dieu hospital in Paris. 

As a noblewoman performing acts of charity, she was welcomed without question. She brought food and wine to the poor and the dying. But what no one knew was that she had laced it with poison. These patients were used to test strength, dosage, and effect. No one suspected a thing.

Their first real target was Marie’s father. Antoine d’Aubray had blocked her relationship, controlled the family fortune, and made it clear he would never hand over a single coin if he could help it. Between June and September of 1666, Marie poisoned him steadily. In her later confession, she admitted to slipping poison into his food nearly thirty times. He died on 10 September. Doctors blamed natural causes. No one asked questions.

A Trail of Death and a Missing Casket

With her father gone, the inheritance passed to her brothers, Antoine-Aymard and François. Marie couldn’t reach them herself. So she hired a man named Jean-Baptiste Glazer, better known as La Chausée. She paid him well and placed him as a servant inside their household. His job was simple. Poison their food and don’t get caught.

On 17 July 1670, Antoine-Aymard died after a sudden illness. Three weeks later, François followed. Both men had suffered stomach pains and weakness. Autopsies later revealed traces of arsenic, but at the time, the symptoms were brushed off as coincidence. Marie had been in Paris during both deaths, giving her the perfect alibi.

Meanwhile, Sainte-Croix was still waiting for his share of the inheritance. He had kept everything. A detailed diary of their crimes. Love letters from Marie. Two signed promises stating she would give him part of the money once it came through. And small glass vials still containing the poison they had used. All of it was locked inside a box marked with a single instruction. To be opened in the event of death before that of Madame de Brinvilliers.

Then Sainte-Croix died. It happened without warning. Some said he poisoned himself by accident while handling the materials in his apartment. Others believed it was deliberate. But once he was dead, the box was opened. Inside was everything. The letters. The notes. The poison. The plot was no longer a secret.

La Chausée was arrested soon after. Under torture, he confessed to everything. He named Marie as the one who had hired him. He described how he had carried out the murders. He was sentenced to death.

Marie fled. She crossed into England, then moved to the Netherlands, trying to avoid capture. But it was too late. Her name was now at the heart of a growing scandal, and the hunt for her had already begun.

Trial, Torture, and Execution

Marie was finally arrested in Liège and brought back to Paris in April 1676. She had spent years hiding in convents and moving between countries, but it hadn’t been enough. The evidence found in Sainte-Croix’s box had never gone away. Now, with La Chausée’s confession on record and a growing sense of public outrage, there was no protection left for her.

Her trial began on 29 April. It was brutal. The court already had everything it needed. There were signed notes, personal letters, witness testimony, and the vials of poison themselves. Marie tried to stall and lie, but it didn’t work. When that failed, the authorities turned to torture.

She was subjected to the water cure. It involved forcing her to drink massive amounts of water in one go. Sixteen pints were poured down her throat while her arms and legs were tied. It was meant to break her resistance, and it did. Afterward, she confessed in full. She admitted to poisoning her father, her brothers, and others. 

On 17 July 1676, Marie Madeleine Marguerite d’Aubray was taken to the Place de Grève. She was beheaded in public. Her body was thrown onto a pyre and burned until there was nothing left. What remained was swept into the Seine.

But that wasn’t the end. Her trial sparked fear at the highest levels of power. If a noblewoman could poison her way through her family, who else might be doing the same? What followed was something even darker, something that would shake the court of Louis XIV to its core.

The Aftermath: Echoes of the Affair of the Poisons

Less than a year later, in 1677, Paris was in the grip of a full-blown panic. What began as whispers in the lower courts became a wave of arrests, confessions, and executions. Midwives, fortune tellers, and so-called “sorcerers” were pulled in first. Then came the nobles. Some had hired poisoners to get rid of husbands. Others to clear the way for inheritance. A few had darker intentions still.

This became known as the Affair of the Poisons. Over the next five years, more than a hundred people were implicated. Some were tortured. Others vanished behind the walls of secret prisons. Even the court of Louis XIV wasn’t untouched. One of his mistresses, Madame de Montespan, was accused of attending black masses and buying poison to secure the king’s love. She was never formally charged, but the suspicion never faded.

The Marquise de Brinvilliers had started a fire. What followed scorched everything from the gutters of Paris to the king’s own bedchamber.