At the same time—though she had not realized this until later— he had been observing her even more shrewdly. Many of her letters to Leibniz, and Leibniz’s letters back to her, had crossed his desk, for he was a member of the Cabinet Noir, whose purpose was to open and read foreign correspondence. He had found her letters to be curiously long, and filled with vapid chatter about hairstyles and the cut of the latest fashions. His true purpose in strolling with her in the gardens of Versailles had been to determine whether she was as empty-headed as she seemed in her letters. The answer, clearly, was no; and moreover she had turned out to know a lot about mathematics, metaphysics, and Natural Philosophy. This had sufficed to send him back to his family château at Juvisy, where he had broken the steganographic code that Eliza had been using to correspond with Leibniz. He could have destroyed, or at least damaged, her then, but he had lacked the desire to. For a kind of seduction had taken place between the two of them, which had not been acted upon until thirteen months ago.