Over the next half hour, Langdon showed them slides of artwork by Michelangelo, Albrecht Dürer, Da Vinci, and many others, demonstrating each artist’s intentional and rigorous adherence to the Divine Proportion in the layout of his compositions. Langdon unveiled PHI in the architectural dimensions of the Greek Parthenon, the pyramids of Egypt, and even the United Nations Building in New York. PHI appeared in the organizational structures of Mozart’s sonatas, Beethoven’s Fifth Symphony, as well as the works of Bartók, Debussy, and Schubert. The number PHI, Langdon told them, was even used by Stradivarius to calculate the exact placement of the f-holes in the construction of his famous violins.

«In closing,» Langdon said, walking to the chalkboard,» we return to symbols» He drew five intersecting lines that formed a five-pointed star. «This symbol is one of the most powerful images you will see this term. Formally known as a pentagram – or pentacle, as the ancients called it – this symbol is considered both divine and magical by many cultures. Can anyone tell me why that might be?»

Stettner, the math major, raised his hand. «Because if you draw a pentagram, the lines automatically divide themselves into segments according to the Divine Proportion.»

Langdon gave the kid a proud nod. «Nice job. Yes, the ratios of line segments in a pentacle allequal PHI, making this symbol the ultimate expression of the Divine Proportion. For this reason, the five-pointed star has always been the symbol for beauty and perfection associated with the goddess and the sacred feminine.»

The girls in class beamed.

«One note, folks. We’ve only touched on Da Vinci today, but we’ll be seeing a lot more of him this semester. Leonardo was a well-documented devotee of the ancient ways of the goddess. Tomorrow, I’ll show you his fresco The Last Supper, which is one of the most astonishing tributes to the sacred feminine you will ever see.»

«You’re kidding, right?» somebody said. «I thought The Last Supper was about Jesus!» Langdon winked. «There are symbols hidden in places you would never imagine.»

«Come on,» Sophie whispered. «What’s wrong? We’re almost there. Hurry!»

Langdon glanced up, feeling himself return from faraway thoughts. He realized he was standing at a dead stop on the stairs, paralyzed by sudden revelation.

O, Draconian devil! Oh, lame saint!

Sophie was looking back at him.

It can’t be that simple, Langdon thought. But he knew of course that it was. There in the bowels of the Louvre… with images of PHI and Da Vinci swirling through his mind, Robert Langdon suddenly and unexpectedly deciphered Saunière’s code.

«O, Draconian devil!» he said. «Oh, lame saint! It’s the simplest kind of code!»

Sophie was stopped on the stairs below him, staring up in confusion. A code? She had been pondering the words all night and had not seen a code. Especially a simple one.

«You said it yourself.» Langdon’s voice reverberated with excitement. «Fibonacci numbers only have meaning in their proper order. Otherwise they’re mathematical gibberish.»

Sophie had no idea what he was talking about. The Fibonacci numbers? She was certain they had been intended as nothing more than a means to get the Cryptography Department involved tonight. They have another purpose? She plunged her hand into her pocket and pulled out the printout, studying her grandfather’s message again.

13-3-2-21-1-1-8-5

O, Draconian devil!

Oh, lame saint!

What about the numbers?

«The scrambled Fibonacci sequence is a clue,» Langdon said, taking the printout. «The numbers area hint as to how to decipher the rest of the message. He wrote the sequence out of order to tell us to apply the same concept to the text. O, Draconian devil? Oh, lame saint? Those lines mean nothing.

They are simply letters written out of order.»

Sophie needed only an instant to process Langdon’s implication, and it seemed laughably simple. «You think this message is… une anagramme?» She stared at him. «Like a word jumble from a newspaper?»

Langdon could see the skepticism on Sophie’s face and certainly understood. Few people realized that anagrams, despite being a trite modern amusement, had a rich history of sacred symbolism.

The mystical teachings of the Kabbala drew heavily on anagrams – rearranging the letters of Hebrew words to derive new meanings. French kings throughout the Renaissance were so convinced that anagrams held magic power that they appointed royal anagrammatists to help them make better decisions by analyzing words in important documents. The Romans actually referred to the study of anagrams as ars magna – «the great art.»

Langdon looked up at Sophie, locking eyes with her now. «Your grandfather’s meaning was right in front of us all along, and he left us more than enough clues to see it.»

Without another word, Langdon pulled a pen from his jacket pocket and rearranged the letters in each line.

O, Draconian devil! Oh, lame saint! was a perfect anagram of… Leonardo Da Vinci! The Mona Lisa!

The Mona Lisa.

For an instant, standing in the exit stairwell, Sophie forgot all about trying to leave the Louvre.

Her shock over the anagram was matched only by her embarrassment at not having deciphered the message herself. Sophie’s expertise in complex cryptanalysis had caused her to overlook simplistic word games, and yet she knew she should have seen it. After all, she was no stranger to anagrams – especially in English.

When she was young, often her grandfather would use anagram games to hone her English spelling. Once he had written the English word» planets» and told Sophie that an astonishing sixty-two other English words of varying lengths could be formed using those same letters. Sophie had spent three days with an English dictionary until she found them all.

«I can’t imagine,» Langdon said, staring at the printout,» how your grandfather created such an intricate anagram in the minutes before he died.»

Sophie knew the explanation, and the realization made her feel even worse. I should have seen this!She now recalled that her grandfather – a wordplay aficionado and art lover – had entertained himself as a young man by creating anagrams of famous works of art. In fact, one of his anagrams had gotten him in trouble once when Sophie was a little girl. While being interviewed by an American art magazine, Saunière had expressed his distaste for the modernist Cubist movement by noting that Picasso’s masterpiece Les Demoiselles d’Avignon was a perfect anagram of vile meaningless doodles.Picasso fans were not amused.

«My grandfather probably created this Mona Lisa anagram long ago,» Sophie said, glancing up at Langdon. And tonight he was forced to use it as a makeshift code.Her grandfather’s voice had called out from beyond with chilling precision.

Leonardo Da Vinci! The Mona Lisa!Why his final words to her referenced the famous painting, Sophie had no idea, but she could think of only one possibility. A disturbing one.

Those were not his final words… .

Was she supposed to visit the Mona Lisa? Had her grandfather left her a message there? The idea seemed perfectly plausible. After all, the famous painting hung in the Salle des Etats – a private viewing chamber accessible only from the Grand Gallery. In fact, Sophie now realized, the doors that opened into the chamber were situated only twenty meters from where her grandfather had been found dead.

He easily could have visited the Mona Lisa before he died.