Langdon explains to Sophie that the documents the Priory protects are called the Sangreal, or Holy Grail. The Grail is not just a cup, as it is most commonly portrayed, but this group of documents. The cup, he explains, is an allegory for something. Langdon remembers showing his manuscript about the Holy Grail to his editor, who reacted dubiously to his theory. (Though Brown does not reveal what this theory is, he makes it clear that it is a controversial theory that does have supporters). Many prominent historians have written about this theory, but it never gained legitimacy because it was not supported by the Bible or the Church.
Sophie realizes that their cabbie is about to turn them in. Holding him at gunpoint, she forces him out of his cab and makes Langdon take the wheel. Langdon can’t drive a stick shift, but they manage to get away.
Silas sits in the room at the Opus Dei safe house, fretting over the fact that even though he killed all of the brothers, he doesn’t know where the secret is. He is also worried that by killing Sister Sandrine, he has put Bishop Aringarosa in danger. Silas considers killing himself. He feels he has let down the only man who has ever helped him. Silas remembers how the Bishop told him that Noah of the Ark was an albino, white like an angel. The Bishop said Silas, too, was destined for great things.
Sophie takes the wheel, and they continue driving toward the address written on the key. As Langdon looks at the key, he thinks about the equal-armed cross engraved on it. The cross is very similar to the symbol used by the Knights Templar, the guardians of the Holy Grail. Nobody has seen the Grail since 1447, when a church fire forced the Priory of Sion to relocate it. Langdon is certain that when Leonardo presided over the Priory of Sion, he knew of the Grail’s whereabouts. Langdon thinks the Grail probably hasn’t been moved since then. Many historians study Leonardo’s work closely in the hopes of discovering the secret of the Holy Grail’s hiding place. It was recently discovered that one of Da Vinci’s paintings, Adoration of the Magi, was painted over after his death in order to cover up a secret message. This discovery has fueled a lot of speculation about the conspiracy around the Grail.
Sophie wonders if the key is to the Grail itself, but Langdon thinks it unlikely that Sophie’s grandfather was so high up in the hierarchy of the Priory of Sion that he had access such classified information. Sophie, remembering the traumatic event in which her grandfather participated, believes it is perfectly plausible that her grandfather had access to such information. They finally reach the address on the back of the key. It is the Depository Bank of Zurich, a Swiss bank.
Bishop Aringarosa arrives at Castel Gandolfo, the Pope’s summer residence, where he meets with the Secretariat Vaticana, the man in charge of Vatican City’s legal matters, as well as with two high-ranking cardinals. They present Aringarosa with a suitcase filled with the Vatican bonds he requested. The Church officials are uncomfortable giving him such a large sum of money, which could easily be traced back to the Church. They don’t know what the Pope will use the money for. Bishop Aringarosa signs an official document, which appears to be his resignation.