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Simonini’s letter: the 19th century text that influenced antisemitic conspiracy theories about the Illuminati

How a conspiracy theory about the origins of the French Revolution became steeped in antisemitism. Nine émigrés executed by guillotine, from La Guillotine in 1793 by H. Fleischmann/Wikimedia

A French Catholic priest called Augustin Barruel is generally regarded as one of history’s most famous conspiracy theorists. His multi-volume 1797 book, Memoirs Illustrating the History of Jacobinism, about an alleged conspiracy that led to the outbreak of the French Revolution, has been reprinted many times and translated into several languages.

Not long after the publication of his work, Barruel was sent a letter by a man called Jean Baptiste Simonini, who alleged that the Jews were also part of the conspiracy. This letter – the original of which has never been found – continues to shape antisemitic conspiracy thinking to this day.

Even before the revolution, Barruel had become famous in France as a conservative writer and journalist. The trainee Jesuit priest strongly opposed the new philosophy of the time – the convictions of Diderot, d'Alembert or even Voltaire – which he regarded as radical.

In his book, Barruel’s conspiracy theory had three component parts. First, he assumed that radical philosophers in Voltaire’s circle had stirred up society. Second, he complained about the multitude of Freemasons in France. Third, he introduced the Illuminati.

The Illuminati was a real secret group, founded in the Bavarian city of Ingolstadt in 1776. Around the time of the Illuminati’s discovery in 1784, a conspiracy theory was stirred up by its staunch enemies accusing the group of wanting to overthrow all thrones and altars and to completely transform society. Even though the Illuminati was eventually disbanded before the outbreak of the French Revolution, many conspiracy theorists believed that its ideas, which were considered radical, had been carried to France by an important member.

For Barruel these three connected conspiracies ultimately led to the rise of the the Jacobins – the most influential political club during the French Revolution.

European conspiracy theories until this point had long presented Jews as evil and disruptive figures. However, Jews played no role in the conspiracy theory Barruel set out in his book. But then he was sent the letter from Simonini.


This article is part of a series tied to the Expert guide to conspiracy theories, a series by The Conversation’s The Anthill podcast. Listen here, on Apple Podcasts or Spotify, or search for The Anthill wherever you get your podcasts.


The Simonini letter

Barruel received a letter from the unknown Jean Baptiste Simonini from Florence on 20 August 1806, written on August 1.

Very little is known about Simonini, but he was not an invention or imagination of Barruel. He held the rank of captain in the Piedmontese army and from 1815 lived in Lilianes in the Aosta Valley.

In his letter, Simonini first congratulated Barruel on his book, but alleged that behind the Freemasons and Illuminati were the Jews. Simonini wrote that he realised this must seem like an exaggeration to Barruel, and so he tried to convince him of his theory by recounting his personal experience. In fact, in Piedmont, Simonini told Barruel, Jews had initiated him into their plans. It’s important to stress here that this is all a conspiracy theory.

Augustin Barruel. Auguste Pidoux, after Desrosiers via Wikimedia.

Barruel was irritated because he hadn’t come across this connection himself. He tried to verify the authenticity of the letter by writing to various personalities, including important bishops. After being told that Simonini could be trusted, Barruel began to study the Jewish history of his conspiracy theory intensely.

In the Jesuit archives in Vanves, just outside Paris, for example, I’ve seen a copy of his book accompanied by notes written by him after 1806. At various points in these notes, Barruel wrote Simonini’s name over a passage about Jews and remarked that it was probably Jews who were pulling the strings.

But Barruel didn’t choose to regard Jews as the main conspirators. He sent Simonini’s letter to some of his Jesuit friends and wrote his opinion of the great conspiracy as a postscript underneath. A variant of such a letter was written shortly before his death in 1820. In it, Barruel made clear that he was now much more convinced that a Freemason conspiracy started the revolution, and that although many Jews were Freemasons, they alone were not to blame for the conspiracy. He wrote that he wanted to prevent a massacre against Jews.

Feeding into antisemitism

But it was too late – copies of Simonini’s letter were already circulating secretly within conservative elites at the beginning of the 19th century and causing damage. It was the letter’s first publication in 1878 in a conservative magazine called Le Contemporain that led it being quoted in various antisemitic conspiracy theory texts.


Read more: Antisemitism: how the origins of history’s oldest hatred still hold sway today


Today, Simonini’s letter is regarded as an influence in the publication of the Protocols of the Elders of Zion, a fake transcript of a secret meeting of Jewish leaders plotting world domination. This widely read conspiracy theory was first published in Russian in 1903.

Even though Simonini’s letter and the publication of the Protocols were ultimately a century apart, the conspiracy theory formed in 1806 was the starting point of a renewed debate about the role of Jews in European society. The conspiracy theories that emerged as part of this debate in the 19th and 20th centuries led to modern antisemitism and all its disastrous consequences.

Questions of origin

Some researchers believe that Simonini’s letter could well be an invention from the 1870s – a time when antisemitism was rising in Europe and when it first appeared publicly in Le Contemporain.

Others assume that Barruel could have written the letter himself. Yet others believe that Simonini’s letter was fabricated by the French police and sent to Barruel owing to his prominence.

My own research has documented how various copies of the letter from the early 1800s have been discovered in Western and Eastern European archives in recent years. This means that the letter is certainly not a product of the 1870s. Nor is it conceivable, based on Barruel’s comments, that he invented it himself.

The problem is that the original copy of the Simonini letter has never been found. It’s believed to be somewhere in the Vatican Apostolic Archive – but so far this has not been verified.

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