Admittedly the keystone was a similar concept then

Admittedly, the keystone was
a similar concept. Then again, tests like this were extremely common in secret societies. The best
known was the Masons', wherein members ascended to higher degrees by proving they could keep
a secret and by performing rituals and various tests of merit over many years. The tasks became
progressively harder until they culminated in a successful candidate's induction as thirty-second-
degree Mason.
"So the keystone is a preuve de mérite," Sophie said. "If a rising Priory sénéchal can open it, he
proves himself worthy of the information it holds."
Langdon nodded. "I forgot you'd had experience with this sort of thing."
"Not only with my grandfather. In cryptology, that's called a 'self-authorizing language.' That is, if
you're smart enough to read it, you're permitted to know what is being said."
Langdon hesitated a moment. "Sophie, you realize that if this is indeed the keystone, your
grandfather's access to it implies he was exceptionally powerful within the Priory of Sion. He
would have to have been one of the highest four members."
Sophie sighed. "He was powerful in a secret society. I'm certain of it. I can only assume it was the
Priory."
Langdon did a double take. "You knew he was in a secret society?"
"I saw some things I wasn't supposed to see ten years ago. We haven't spoken since." She paused.
"My grandfather was not only a ranking top member of the group... I believe he was the top
member."
Langdon could not believe what she had just said. "Grand Master? But... there's no way you could
know that!"

"I'd rather not talk about it." Sophie looked away, her expression as determined as it was pained.
Langdon sat in stunned silence. Jacques Saunière? Grand Master? Despite the astonishing
repercussions if it were true, Langdon had the eerie sensation it almost made perfect sense. After
all, previous Priory Grand Masters had also been distinguished public figures with artistic souls.
Proof of that fact had been uncovered years ago in Paris's Bibliothèque Nationale in papers that
became known as Les Dossiers Secrets.
Every Priory historian and Grail buff had read the Dossiers. Cataloged under Number 4° lm
1
249,
the Dossiers Secrets had been authenticated by many specialists and incontrovertibly confirmed
what historians had suspected for a long time: Priory Grand Masters included Leonardo da Vinci,
Botticelli, Sir Isaac Newton, Victor Hugo, and, more recently, Jean Cocteau, the famous Parisian
artist.
Why not Jacques Saunière?
Langdon's incredulity intensified with the realization that he had been slated to meet Saunière
tonight. The Priory Grand Master called a meeting with me. Why? To make artistic small talk? It
suddenly seemed unlikely. After all, if Langdon's instincts were correct, the Grand Master of the
Priory of Sion had just transferred the brotherhood's legendary keystone to his granddaughter and
simultaneously commanded her to find Robert Langdon.