Summary: Langdon hypothesizes that the cryptex is, itself, the Priory of Sion’s keystone—not the literal, wedge-shaped rock at the top of an arch, but the “key” to finding the location of the Holy Grail. He explains to Sophie that the Priory developed the keystone only in recent decades, as a means of protecting the secret of the Grail’s location against electronic surveillance. Each new sénéchal selected into the Brotherhood (the top four members of the Priory) must open the Keystone as a test of merit, in order to prove their worthiness to know the Grail’s location. Sophie confirms for Langdon that her grandfather was a high-ranking member of a secret society; Langdon surmises that Saunière was, indeed, the Grand Master. Unexpectedly, Vernet pulls the armored truck over—and pulls a pistol on his passengers.
Analysis: This chapter reveals more of the lore surrounding the Grail and its keepers, this time drawing the Masons into the tapestry—albeit as more of a parallel analogy to the Priory, rather than critical players in the plot itself. Another secretive society often implicated in conspiracy theories, the Freemasons describe themselves as “the oldest and largest world wide fraternity dedicated to the Brotherhood of Man under the Fatherhood of a Supreme Being. Although of a religious nature, Freemasonry is not a religion. It urges its members, however, to be faithful and devoted to their own religious beliefs” (www.freemasonry.org). The origin of the Masons’ secretive nature given in the novel (like so much of the novel’s information) certainly sounds plausible: “The secret knowledge of how to use a wedged keystone to build a vaulted archway was part of the wisdom that had made the Masons such wealthy craftsmen, and it was a secret they guarded carefully” (p. 221). Interestingly, the Masons’ international research association is known as the Philalethes Society—the lovers of truth. Their presence in Brown’s novel is fitting, then, given that Langdon and Sophie can fairly be described as “lovers of truth.”
Langdon primarily invokes the Masons, however, for their use of preuves de mérite, “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” (p. 223). Sophie connects the “treasure hunts” that her grandfather would devise for her on her birthday with the merit tests of secret societies. Again, Brown is laying the groundwork for future revelations, and is leading readers to expect that Sophie will need to pass other tests of merit before she is ultimately rewarded with the truth: the truth about the Grail, and the truth about her family that Saunière promised her in his final communication to her. In fact, Langdon may already be intuiting the connection between those two truths when he muses, “He had not yet had a chance to explain to Sophie the true nature of the Holy Grail” (p. 222). True to Brown’s technique, the author does not leave us much time or space to reflect on that comment at present; but it will prove important in the final solution to this “Grail quest.”