Gold Key
The Gold Key is a laser-cut cruciform key that Jacques Saunière hid behind Leonardo da Vinci's Madonna of the Rocks painting in the Louvre, intended for his granddaughter Sophie Neveu. It bears the Priory of Sion's official seal—a fleur-de-lis with the initials P.S.—and provides access to a safe-deposit box at the Depository Bank of Zurich, which contains the Priory's keystone, a marble cryptex designed by Leonardo da Vinci that holds a map to the Holy Grail.
Identity and Design
The Gold Key is a heavy, cruciform object with a triangular, prismatic shaft. Its head is a square cross with four arms of equal length, a shape that predates Christianity by fifteen hundred years and is considered a peaceful cross, symbolizing the union of male and female. The shaft is pockmarked with hundreds of finely tooled, randomly scattered hexagonal indentations, which are read by an electric eye, making the key impossible to duplicate. On the center of the cross is an intricately embossed stylized fleur-de-lis with the initials P.S., which Robert Langdon identifies as the official device of the Priory of Sion. Sophie Neveu recalls seeing this same key as a child, when her grandfather told her it opened a box where he kept many secrets and that it had her name on it, referring to the initials P.S. as her secret code for "Princesse Sophie."
Discovery and Hidden Message
Sophie finds the key wedged behind the frame of Leonardo da Vinci's Madonna of the Rocks in the Salle des Etats, having been guided there by the anagram "O, Draconian devil! Oh, lame saint!" which decodes to "Leonardo da Vinci! The Mona Lisa!" and the message "So dark the con of man" scrawled on the Mona Lisa's protective glass. The key had been cleaned with rubbing alcohol, which initially masked a hidden message. When Sophie uses a UV black light, a luminescent address appears on the back of the key: "24 Rue Haxo." This address leads them to the Depository Bank of Zurich, where the key is used to access a safe-deposit box.
Function and Significance
The Gold Key is the physical means to access the Priory of Sion's keystone. At the bank, the key is inserted into a triangular hole at the gate, in the elevator, and at the vault podium. The key alone is only half of the identification; it must be paired with a ten-digit account number. Sophie deduces that the scrambled Fibonacci sequence (13-3-2-21-1-1-8-5) left by her grandfather on the Louvre floor is a clue, and she correctly enters the sequence in its proper order (1-1-2-3-5-8-13-21) as the account number. The key then authorizes the robotic retrieval of a heavy plastic crate containing a rosewood box with an inlaid five-petal rose, which holds the marble cryptex—the keystone that, when unlocked, reveals a map to the Holy Grail. The key thus serves as the final link in Saunière's elaborate treasure hunt, ensuring that only Sophie could retrieve the keystone and continue the quest to protect the secret of the Sangreal.
