Studying conspiracy theories in the longue durée, you are struck by the incredible stability of their basic tropes and tableux. They are at once endlessly creative and improvisational, but somehow, they don't seem to change all that much.

The monk Paul of Saint-Père de Chartres's late 11th century narrative of the Orléans heresy, for instance, features a clandestine meeting, satanic worship, child sacrifice, and a sacrament made from the ashes of the young victim which bound communicants irrevocably to the sect.

Swap adrenochrome for ashes and this could sit comfortably on any lurid Pizzagate subreddit.

And the imagined malefactors can seamlessly evolve from heretics to Jews to freemasons to globalists without much alteration of the underlying details. The kinds of things such invisible enemies are imagined to do is stable, even as their actual identity is fluid.

Picking up an old thread on how the basic architecture of modern conspiracy theory barely changes. Here's Thomas of Monmouth's late 12th c. Life of Miracles of St. William of Norwich, one of the medieval foundations of the blood libel that Jews ritually murdered Christians.

Thomas's source, the converted Jew Theobald reports that the "chief Men and Rabbis" gather annually in Narbonne to select the country and city in which the ritual murder is to occur that year. This is seven centuries before the Protocols of the Elders of Zion.

The repertoire for depicting the secret machinations of invisible enemies is both strikingly limited and highly stable. The scenes are just fixed in the Western imagination.

Anti-popery anticipates much of antisemitism. Here's a proposal in the Addled Parliament of 1614 that likens Catholics to blood-sucking 'horse leeches,' moves they should stripped of civil liberties and forced to wear 'yellow caps' to distinguish them from Protestants.