Saint-Martin-des-Champs Art and Craft Museum

The Saint-Martin-des-Champs Monastery / Museum of Arts and Crafts links an abbey’s history to the modern Conservatoire des Arts et Métiers, the setting of the Foucault Pendulum and a pivotal site in the novel’s Plan. The characters turn the institution’s layered past into apparent evidence of continuity among Templar history, Francis Bacon, the House of Solomon, and the Pendulum—an imaginative chain whose ingenuity also exposes how readily coincidence can be made to look like design.

From Abbey to Conservatoire

In the collaborators’ reconstruction, the prior of Saint Albans, one of those involved in organizing the Council of Troyes, was also abbot of Saint-Martin-des-Champs. The abbey later housed the Conservatoire des Arts et Métiers, allowing the history of the site to become a bridge between the medieval Templars and a modern Paris institution.

Casaubon adds a second connection: the Conservatoire was conceived as a homage to Francis Bacon. He cites two measures attributed to the Convention in the same year: one authorized the printing of Bacon’s complete works, while another provided for a house of arts and trades modeled on the House of Solomon in Bacon’s New Atlantis, collecting humanity’s inventions. In the trio’s growing web of associations, the institution is therefore not merely a museum but a material embodiment of Baconian knowledge.

The Pendulum and the Plan

The building’s most consequential object is the Foucault Pendulum. Belbo immediately connects it to the Conservatoire, but Casaubon objects that the Pendulum was invented and installed only in the nineteenth century, too late to be treated as an ancient link in the chain. Belbo resists discarding it: he sees a resemblance between the Pendulum and John Dee’s Monad Hieroglyph, a talisman said to concentrate the wisdom of the universe.

That exchange shows the Plan being assembled in practice. Casaubon initially tests the chronology and rejects an anachronistic connection; Belbo counters by shifting from historical descent to visual and symbolic resemblance. Later, Casaubon gives the Pendulum a function within their scheme after encountering a text about cathedral builders who supposedly inferred the Earth’s rotation from a plumb line suspended from a vault’s keystone. In this imagined history, the Conservatoire’s instrument becomes an answer to a question the conspiratorial narrative has first created: what role could the Pendulum play in the Plan?

An Institution as Evidence—and as a Trap

The Conservatoire’s multiple identities make it especially useful to the trio’s pattern-making. Its association with a medieval abbey, Bacon’s House of Solomon, collections of invention, and the nineteenth-century Pendulum lets distinct periods appear to converge at one location. Each connection supplies a fresh route for interpretation, even when the links depend on different kinds of evidence—administrative history, institutional homage, chronology, or resemblance.

The novel later sharpens the irony through Lia’s explanation of the coded Provins text. The phrase about the thirty-six invisibles, she argues, belongs to seventeenth-century Rosicrucian usage, while the Trithemius cipher points to a later date; rather than proving that Rosicrucians inherited a Templar plan, the message may have been a modern exercise by Ingolf. Against that skeptical account, the Conservatoire’s history remains a vivid example of how the Plan acquires force: a real place accumulates real historical associations, and the characters make their convergence feel like proof of a single hidden design.