The north-south stripe had been known as the Rose Line. For centuries, the symbol of the Rose had been associated with maps and guiding souls in the proper direction. The Compass Rose— drawn on almost every map—indicated North, East, South, and West. Originally known as the Wind Rose, it denoted the directions of the thirty-two winds, blowing from the directions of eight major winds, eight half-winds, and sixteen quarter-winds. When diagrammed inside a circle, these thirty-two points of the compass perfectly resembled a traditional thirty-two petal rose bloom. To this day, the fundamental navigational tool was still known as a Compass Rose, its northernmost direction still marked by an arrowhead … or, more commonly, the symbol of the fleur-de-lis.

On a globe, a Rose Line—also called a meridian or longitude—was any imaginary line drawn from the North Pole to the South Pole. There were, of course, an infinite number of Rose Lines because every point on the globe could have a longitude drawn through it connecting north and south poles. The question for early navigators was which of these lines would be called the Rose Line—the zero

longitude—the line from which all other longitudes on earth would be measured.

Today that line was in Greenwich, England. But it had not always been.

Long before the establishment of Greenwich as the prime meridian, the zero longitude of the entire world had passed directly through Paris, and through the Church of Saint-Sulpice. The brass marker in Saint-Sulpice was a memorial to the world’s first prime meridian, and although Greenwich had stripped Paris of the honor in 1888, the original Rose Line was still visible today.

“And so the legend is true,” the Teacher had told Silas. “The Priory keystone has been said to lie ‘beneath the Sign of the Rose.’ ”

Now, still on his knees in a pew, Silas glanced around the church and listened to make sure no one was there. For a moment, he thought he heard a rustling in the choir balcony. He turned and gazed up for several seconds. Nothing.

I am alone.

Standing now, he faced the altar and genuflected three times. Then he turned left and followed the brass line due north toward the obelisk.

At that moment, at Leonardo da Vinci International Airport in Rome, the jolt of tires hitting the runway startled Bishop Aringarosa from his slumber.

I drifted off, he thought, impressed he was relaxed enough to sleep.

“Benvenuto a Roma,” the intercom announced.

Sitting up, Aringarosa straightened his black cassock and allowed himself a rare smile. This was one trip he had been happy to make. I have been on the defensive for too long. Tonight, however, the rules had changed. Only five months ago, Aringarosa had feared for the future of the Faith. Now, as if by the will of God, the solution had presented itself.

Divine intervention.

If all went as planned tonight in Paris, Aringarosa would soon be in possession of something that would make him the most powerful

man in Christendom.

CHAPTER 23

Sophie arrived breathless outside the large wooden doors of the Salle des Etats—the room that housed the Mona Lisa. Before entering, she gazed reluctantly farther down the hall, twenty yards or so, to the spot where her grandfather’s body still lay under the spotlight.

The remorse that gripped her was powerful and sudden, a deep sadness laced with guilt. The man had reached out to her so many times over the past ten years, and yet Sophie had remained immovable—leaving his letters and packages unopened in a bottom drawer and denying his efforts to see her. He lied to me! Kept appalling secrets! What was I supposed to do? And so she had blocked him out. Completely.

Now her grandfather was dead, and he was talking to her from the grave.

The Mona Lisa.

She reached for the huge wooden doors, and pushed. The entryway yawned open. Sophie stood on the threshold a moment, scanning the large rectangular chamber beyond. It too was bathed in a soft red light. The Salle des Etats was one of this museum’s rare culs-de-sac—a dead end and the only room off the middle of the Grand Gallery. This door, the chamber’s sole point of entry, faced a dominating fifteen-foot Botticelli on the far wall. Beneath it, centered on the parquet floor, an immense octagonal viewing divan served as a welcome respite for thousands of visitors to rest their legs while they admired the Louvre’s most valuable asset.

Even before Sophie entered, though, she knew she was missing something. A black light. She gazed down the hall at her grandfather under the lights in the distance, surrounded by electronic gear. If he had written anything in here, he almost certainly would have written it with the watermark stylus.

Taking a deep breath, Sophie hurried down to the well-lit crime scene. Unable to look at her grandfather, she focused solely on the

PTS tools. Finding a small ultraviolet penlight, she slipped it in the pocket of her sweater and hurried back up the hallway toward the open doors of the Salle des Etats.

Sophie turned the corner and stepped over the threshold. Her entrance, however, was met by an unexpected sound of muffled footsteps racing toward her from inside the chamber. There’s someone in here! A ghostly figure emerged suddenly from out of the reddish haze. Sophie jumped back.

“There you are!” Langdon’s hoarse whisper cut the air as his silhouette slid to a stop in front of her.

Her relief was only momentary. “Robert, I told you to get out of here! If Fache—”

“Where were you?”

“I had to get the black light,” she whispered, holding it up. “If my grandfather left me a message—”

“Sophie, listen.” Langdon caught his breath as his blue eyes held her firmly. “The letters P.S…. do they mean anything else to you? Anything at all?”

Afraid their voices might echo down the hall, Sophie pulled him into the Salle des Etats and closed the enormous twin doors silently, sealing them inside. “I told you, the initials mean Princess Sophie.”

“I know, but did you ever see them anywhere else? Did your grandfather ever use P.S. in any other way? As a monogram, or maybe on stationery or a personal item?”

The question startled her. How would Robert know that? Sophie had indeed seen the initials P.S. once before, in a kind of monogram. It was the day before her ninth birthday. She was secretly combing the house, searching for hidden birthday presents. Even then, she could not bear secrets kept from her. What did Grand-père get for me this year? She dug through cupboards and drawers. Did he get me the doll I wanted? Where would he hide it?

Finding nothing in the entire house, Sophie mustered the courage to sneak into her grandfather’s bedroom. The room was off-limits to her, but her grandfather was downstairs asleep on the couch.

I’ll just take a fast peek!

Tiptoeing across the creaky wood floor to his closet, Sophie peered on the shelves behind his clothing. Nothing. Next she looked under the bed. Still nothing. Moving to his bureau, she opened the drawers and one by one began pawing carefully through them. There must be something for me here! As she reached the bottom drawer, she still had not found any hint of a doll. Dejected, she opened the final drawer and pulled aside some black clothes she had never seen him wear. She was about to close the drawer when her eyes caught a glint of gold in the back of the drawer. It looked like a pocket watch chain, but she knew he didn’t wear one. Her heart raced as she realized what it must be.

A necklace!

Sophie carefully pulled the chain from the drawer. To her surprise, on the end was a brilliant gold key. Heavy and shimmering. Spellbound, she held it up. It looked like no key she had ever seen. Most keys were flat with jagged teeth, but this one had a triangular column with little pockmarks all over it. Its large golden head was in the shape of a cross, but not a normal cross. This was an even- armed one, like a plus sign. Embossed in the middle of the cross was a strange symbol—two letters intertwined with some kind of flowery design.

“P.S.,” she whispered, scowling as she read the letters. Whatever could this be?

“Sophie?” her grandfather spoke from the doorway.

Startled, she spun, dropping the key on the floor with a loud clang. She stared down at the key, afraid to look up at her grandfather’s face. “I … was looking for my birthday present,” she said, hanging her head, knowing she had betrayed his trust.

For what seemed like an eternity, her grandfather stood silently in the doorway. Finally, he let out a long troubled breath. “Pick up the key, Sophie.”

Sophie retrieved the key.

Her grandfather walked in. “Sophie, you need to respect other people’s privacy.” Gently, he knelt down and took the key from her. “This key is very special. If you had lost it …”

Her grandfather’s quiet voice made Sophie feel even worse. “I’m sorry, Grand-père. I really am.” She paused. “I thought it was a necklace for my birthday.”

He gazed at her for several seconds. “I’ll say this once more, Sophie, because it’s important. You need to learn to respect other people’s privacy.”

“Yes, Grand-père.

“We’ll talk about this some other time. Right now, the garden needs to be weeded.”

Sophie hurried outside to do her chores.

The next morning, Sophie received no birthday present from her grandfather. She hadn’t expected one, not after what she had done. But he didn’t even wish her happy birthday all day. Sadly, she trudged up to bed that night. As she climbed in, though, she found a note card lying on her pillow. On the card was written a simple riddle. Even before she solved the riddle, she was smiling. I know what this is! Her grandfather had done this for her last Christmas morning.

A treasure hunt!

Eagerly, she pored over the riddle until she solved it. The solution pointed her to another part of the house, where she found another card and another riddle. She solved this one too, racing on to the next card. Running wildly, she darted back and forth across the house, from clue to clue, until at last she found a clue that directed her back to her own bedroom. Sophie dashed up the stairs, rushed into her room, and stopped in her tracks. There in the middle of the room sat a shining red bicycle with a ribbon tied to the handlebars. Sophie shrieked with delight.

“I know you asked for a doll,” her grandfather said, smiling in the corner. “I thought you might like this even better.”

The next day, her grandfather taught her to ride, running beside her down the walkway. When Sophie steered out over the thick lawn and lost her balance, they both went tumbling onto the grass, rolling and laughing.

“Grand-père,” Sophie said, hugging him. “I’m really sorry about the key.”

“I know, sweetie. You’re forgiven. I can’t possibly stay mad at you.

Grandfathers and granddaughters always forgive each other.”

Sophie knew she shouldn’t ask, but she couldn’t help it. “What does it open? I never saw a key like that. It was very pretty.”

Her grandfather was silent a long moment, and Sophie could see he was uncertain how to answer. Grand-père never lies. “It opens a box,” he finally said. “Where I keep many secrets.”

Sophie pouted. “I hate secrets!”

“I know, but these are important secrets. And someday, you’ll learn to appreciate them as much as I do.”

“I saw letters on the key, and a flower.”

“Yes, that’s my favorite flower. It’s called a fleur-de-lis. We have them in the garden. The white ones. In English we call that kind of flower a lily.”

“I know those! They’re my favorite too!”

“Then I’ll make a deal with you.” Her grandfather’s eyebrows raised the way they always did when he was about to give her a challenge. “If you can keep my key a secret, and never talk about it ever again, to me or anybody, then someday I will give it to you.”

Sophie couldn’t believe her ears. “You will?

“I promise. When the time comes, the key will be yours. It has your name on it.”

Sophie scowled. “No it doesn’t. It said P.S. My name isn’t P.S.!”

Her grandfather lowered his voice and looked around as if to make sure no one was listening. “Okay, Sophie, if you must know, P.S. is a code. It’s your secret initials.”

Her eyes went wide. “I have secret initials?”

“Of course. Granddaughters always have secret initials that only their grandfathers know.”

“P.S.?”

He tickled her. “Princesse Sophie.” She giggled. “I’m not a princess!” He winked. “You are to me.”

From that day on, they never again spoke of the key. And she became his Princess Sophie.

Inside the Salle des Etats, Sophie stood in silence and endured the sharp pang of loss.

“The initials,” Langdon whispered, eyeing her strangely. “Have you seen them?”

Sophie sensed her grandfather’s voice whispering in the corridors of the museum. Never speak of this key, Sophie. To me or to anyone. She knew she had failed him in forgiveness, and she wondered if she could break his trust again. P.S. Find Robert Langdon. Her grandfather wanted Langdon to help. Sophie nodded. “Yes, I saw the initials P.S. once. When I was very young.”

“Where?”

Sophie hesitated. “On something very important to him.”

Langdon locked eyes with her. “Sophie, this is crucial. Can you tell me if the initials appeared with a symbol? A fleur-de-lis?”

Sophie felt herself staggering backward in amazement. “But … how could you possibly know that!”

Langdon exhaled and lowered his voice. “I’m fairly certain your grandfather was a member of a secret society. A very old covert brotherhood.”

Sophie felt a knot tighten in her stomach. She was certain of it too. For ten years she had tried to forget the incident that had confirmed that horrifying fact for her. She had witnessed something unthinkable. Unforgivable.

“The fleur-de-lis,” Langdon said, “combined with the initials P.S., that is the brotherhood’s official device. Their coat of arms. Their logo.”

“How do you know this?” Sophie was praying Langdon was not going to tell her that he himself was a member.

“I’ve written about this group,” he said, his voice tremulous with excitement. “Researching the symbols of secret societies is a specialty of mine. They call themselves the Prieuré de Sion—the Priory of Sion. They’re based here in France and attract powerful members from all over Europe. In fact, they are one of the oldest surviving secret societies on earth.”

Sophie had never heard of them.

Langdon was talking in rapid bursts now. “The Priory’s membership has included some of history’s most cultured individuals: men like Botticelli, Sir Isaac Newton, Victor Hugo.” He paused, his voice brimming now with academic zeal. “And, Leonardo da Vinci.”