had made the Masons such wealthy craftsmen, and it was a secret they guarded carefully. Keystones had always had a tradition of secrecy. And yet, the stone cylinder in the rosewood box was obviously something quite different. The Priory keystone - if this was indeed what they were holding - was not at all what Langdon had imagined.
"The Priory keystone is not my specialty," Langdon admitted. "My interest in the Holy Grail is primarily symbologic, so I tend to ignore the plethora of lore regarding how to actually find it."
Sophie's eyebrows arched. "Find the Holy Grail?"
Langdon gave an uneasy nod, speaking his next words carefully. "Sophie, according to Priory lore, the keystone is an encoded map... a map that reveals the hiding place of the Holy Grail." Sophie's face went blank. "And you think this is it?" Langdon didn't know what to say. Even to him it sounded unbelievable, and yet the keystone was the only logical conclusion he could muster. An encrypted stone, hidden beneath the sign of theRose.
The idea that the cryptex had been designed by Leonardo Da Vinci - former Grand Master of the Priory of Sion - shone as another tantalizing indicator that this was indeed the Priory keystone. A former Grand Master's blueprint...brought to life centuries later by another Priory member.The bond was too palpable to dismiss.
For the last decade, historians had been searching for the keystone in French churches. Grail seekers, familiar with the Priory's history of cryptic double-talk, had concluded la clef de voute was a literal keystone - an architectural wedge - an engraved, encrypted stone, inserted into a vaulted archway in a church. Beneath the sign of the Rose.In architecture, there was no shortage of roses. Rose windows.Rosette reliefs.And, of course, an abundance of cinquefoils - the five-petaled decorative flowers often found at the top of archways, directly over the keystone. The hiding place seemed diabolically simple. The map to the Holy Grail was incorporated high in an archway of some forgotten church, mocking the blind churchgoers who wandered beneath it.
"This cryptex can't be the keystone," Sophie argued. "It's not old enough. I'm certain my grandfather made this. It can't be part of any ancient Grail legend."
"Actually," Langdon replied, feeling a tingle of excitement ripple through him," the keystone is believed to have been created by the Priory sometime in the past couple of decades."
Sophie's eyes flashed disbelief. "But if this cryptex reveals the hiding place of the Holy Grail, why would my grandfather give it to me? I have no idea how to open it or what to do with it. I don't even know what the Holy Grail is!"
Langdon realized to his surprise that she was right. He had not yet had a chance to explain to Sophie the true nature of the Holy Grail. That story would have to wait. At the moment, they were focused on the keystone.
If that is indeed what this is... .
Against the hum of the bulletproof wheels beneath them, Langdon quickly explained to Sophie everything he had heard about the keystone. Allegedly, for centuries, the Priory's biggest secret - the location of the Holy Grail - was never written down. For security's sake, it was verbally transferred to each new rising senechal at a clandestine ceremony. However, at some point during the last century, whisperings began to surface that the Priory policy had changed. Perhaps it was on account of new electronic eavesdropping capabilities, but the Priory vowed never again even to speak the location of the sacred hiding place.
"But then how could they pass on the secret?" Sophie asked.
"That's where the keystone comes in," Langdon explained. "When one of the top four members died, the remaining three would choose from the lower echelons the next candidate to ascend as senechal.Rather than telling the new senechal where the Grail was hidden, they gave him a test through which he could prove he was worthy."
Sophie looked unsettled by this, and Langdon suddenly recalled her mentioning how her grandfather used to make treasure hunts for her - preuves de merite.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 merite,"Sophie said. "If a