A specter is haunting America — the specter of conspiracy. Millions of Americans have embraced far-right QAnon conspiracy theories. The theories, which posit that President Trump is “battling a cabal of deep-state saboteurs who worship Satan and traffic children for sex,” have been flagged as a threat by the FBI. And yet, they have become so common that Trump regularly echoes them. And now, a QAnon supporter, Marjorie Taylor Greene, just won the Republican primary in Georgia’s 14th Congressional District.

While the speed and reach of these theories is new thanks to social media, we have been here before. Indeed, the United States has a long history of conspiratorial thinking — from obsessions with the Masons and the Illuminati in the 19th century to the recent tea party movement and the birtherism supported by Trump. But conspiratorial thinking runs much deeper than just a few scattered moments in American political history. In fact, conspiracy theories have long existed as a way for individuals to understand momentous and unsettling change happening around them. Mostly finding followers among those on the losing side of this change, they are also frequently embraced by politicians who may not even believe them but use the theories to their political advantage anyhow.

Enter the French connection. Some of the earliest conspiracy theories in America, which held that the Illuminati and Masons were seeking to subvert established governments and Christianity everywhere, were rooted in France and the work of a little-known ex-Jesuit emigre, Augustin Barruel.

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Barruel saw the French Revolution as the culmination of a long-standing, insidious conspiracy orchestrated by “Voltaire, Rousseau, and other philosophers, who plotted — with the Freemasons and the German Illuminati — to destroy the monarchy and Catholicism in France,” historian Amos Hofman has argued. For this reason, Hofman sees Barruel’s work as “the first systematic attempt to discuss the role of conspiracy in a revolution.”

Barruel was trying to explain all of the events of the Revolution — a sprawling, complex event that overthrew the French monarchy, sidelined the church and proclaimed “liberty, equality and fraternity” for all — though a single theory wrought of intrigue and machination. He focused on “human agency” as the singular cause of the revolution.