A natural blemish? Or maybe … something else. Langdon immediately spun and pointed to a hinged panel of marble on the wall behind them. “Look in there,” he told Sienna. “See if there are towels.”

Sienna looked skeptical, but obeyed, opening the discreetly hidden cupboard, which contained three items—a valve for controlling the water level in the font, a light switch for controlling the spotlight above the font, and … a stack of linen towels.

Sienna gave Langdon a surprised look, but Langdon had toured enough churches worldwide to know that baptismal fonts almost always afforded their priests easy access to emergency swaddling cloths—the unpredictability of infants’ bladders a universal risk of christenings.

“Good,” he said, eyeing the towels. “Hold the mask a second?” He gently transferred the mask to Sienna’s hands and then set to work.

First, Langdon retrieved the hexagonal lid and heaved it back up onto the font to restore the small, altarlike table they had first seen. Then he grabbed several of the linen towels from the cupboard and spread them out like a tablecloth. Finally, he flipped the font’s light switch, and the spotlight directly overhead sprang to life, illuminating the baptismal area and shining brightly down on the covered surface.

Sienna gently laid the mask on the font while Langdon retrieved more towels, which he used like oven mitts to slide the mask from the Ziploc bag, careful not to touch it with his bare hands. Moments later, Dante’s death mask lay unsheathed and naked, faceup beneath the bright light, like the head of an anesthetized patient on an operating table.

The mask’s dramatic texturing appeared even more unsettling in the light, the creases and wrinkles of old age accentuated by the discolored plaster. Langdon wasted no time using his makeshift mitts to flip the mask over and lay it facedown.

The back side of the mask looked markedly less aged than the front—clean and white rather than dingy and yellow.

Sienna cocked her head, looking puzzled. “Does this side look newer to you?”

Admittedly, the color difference was more emphatic than Langdon would have imagined, but this side was most certainly the same age as the front. “Uneven aging,” he said. “The back of the mask has been shielded by the display case so has never suffered the aging effects of sunlight.” Langdon made a mental note to double the SPF of his sunscreen.

“Hold on,” Sienna said, leaning in close to the mask. “Look! On the forehead! That must be what you and Ignazio saw.”

Langdon’s eyes moved quickly across the smooth white surface to the same discoloration he had spied earlier through the plastic—a faint line of markings that ran horizontally across the inside of Dante’s forehead. Now, however, in the stark light, Langdon saw clearly that these markings were not a natural blemish … they were man-made.

“It’s … writing,” Sienna whispered, the words catching in her throat. “But …”

Langdon studied the inscription on the plaster. It was a single row of letters—handwritten in a florid script of faint brownish yellow.

“That’s all it says?” Sienna said, sounding almost angry.

Langdon barely heard her. Who wrote this? he wondered. Someone in Dante’s era? It seemed unlikely. If so, some art historian would have spotted it long ago during regular cleaning or restoration, and the writing would have become part of the lore of the mask. Langdon had never heard of it.

A far more likely source quickly materialized in his mind.

Bertrand Zobrist.

Zobrist was the mask’s owner and therefore could easily have requested private access to it whenever he wanted. He could have written the text on the back of the mask fairly recently and then replaced it in the antique case without anyone ever knowing. The mask’s owner, Marta had told them, won’t even permit our staff to open the case without him present.

Langdon quickly explained his theory.

Sienna seemed to accept his logic, and yet the prospect clearly troubled her. “It makes no sense,” she said, looking restless. “If we believe Zobrist secretly wrote something on the back of the Dante death mask, and he also went to the trouble to create that little projector to point to the mask … then why didn’t he write something more meaningful? I mean, it’s senseless! You and I have been looking all day for the mask, and this is all we find?”

Langdon redirected his focus to the text on the back of the mask. The handwritten message was very brief—only seven letters long—and admittedly looked entirely purposeless.

Sienna’s frustration is certainly understandable.

Langdon, however, felt the familiar thrill of imminent revelation, having realized almost instantly that these seven letters would tell him everything he needed to know about what he and Sienna were to do next.

Furthermore, he had detected a faint odor to the mask—a familiar scent that divulged why the plaster on the back was so much whiter than the front … and the difference had nothing to do with aging or sunlight.

“I don’t understand,” Sienna said. “The letters are all the same.”

Langdon nodded calmly as he studied the line of text—seven identical letters carefully inscribed in calligraphy across the inside of Dante’s forehead.

PPPPPPP

“Seven Ps,” Sienna said. “What are we supposed to do with this?”

Langdon smiled calmly and raised his eyes to hers. “I suggest we do precisely what this message tells us to do.”

Sienna stared. “Seven Ps is … a message?”

“It is,” he said with a grin. “And if you’ve studied Dante, it’s a very clear one.”

Outside the Baptistry of San Giovanni, the man with the necktie wiped his fingernails on his handkerchief and dabbed at the pustules on his neck. He tried to ignore the burning in his eyes as he squinted at his destination.

The tourist entrance.

Outside the door, a wearied docent in a blazer smoked a cigarette and redirected tourists who apparently couldn’t decipher the building’s schedule, which was written in international time.

APERTURA 1300–1700.

The man with the rash checked his watch. It was 10:02 A.M. The baptistry was closed for another few hours. He watched the docent for a while and then made up his mind. He removed the gold stud from his ear and pocketed it. Then he pulled out his wallet and checked its contents. In addition to assorted credit cards and a wad of euros, he was carrying over three thousand U.S. dollars in cash.

Thankfully, avarice was an international sin.

CHAPTER 57

Peccatum … Peccatum … Peccatum …

The seven Ps written on the back of Dante’s death mask immediately pulled Langdon’s thoughts back into the text of The Divine Comedy. For a moment he was back onstage in Vienna, presenting his lecture “Divine Dante: Symbols of Hell.”

“We have now descended,” his voice resounded over the speakers, “passing down through the nine rings of hell to the center of the earth, coming face-to-face with Satan himself.”

Langdon moved from slide to slide through a series of three-headed Satans from various works of art—Botticelli’s Mappa, the Florence baptistry’s mosaic, and Andrea di Cione’s terrifying black demon, its fur soiled with the crimson blood of its victims.

“Together,” Langdon continued, “we have climbed down the shaggy chest of Satan, reversed direction as gravity shifted, and emerged from the gloomy underworld … once again to see the stars.”

Langdon advanced slides until he reached an image he had shown earlier—the iconic Domenico di Michelino painting from inside the duomo, which depicted the red-robed Dante standing outside the walls of Florence. “And if you look carefully … you will see those stars.”

Langdon pointed to the star-filled sky that arched above Dante’s head. “As you see, the heavens are constructed in a series of nine concentric spheres around the earth. This nine-tiered structure of paradise is intended to reflect and balance the nine rings of the underworld. As you’ve probably noticed, the number nine is a recurring theme for Dante.”

Langdon paused, taking a sip of water and letting the crowd catch their breath after their harrowing descent and final exit from hell.

“So, after enduring the horrors of the inferno, you must all be very excited to move toward paradise. Unfortunately, in the world of Dante, nothing is ever simple.” He heaved a dramatic sigh. “To ascend to paradise we all must—both figuratively and literally—climb a mountain.”

Langdon pointed to the Michelino painting. On the horizon, behind Dante, the audience could see a single cone-shaped mountain rising into the heavens. Spiraling up the mountain, a pathway circled the cone repeatedly—nine times—ascending in ever-tightening terraces toward the top. Along the pathway, naked figures trudged upward in misery, enduring various penances on the way.

“I give you Mount Purgatory,” Langdon announced. “And sadly, this grueling, nine-ringed ascent is the only route from the depths of inferno to the glory of paradise. On this path, you can see the repentant souls ascending … each paying an appropriate price for a given sin. The envious must climb with their eyes sewn shut so they cannot covet; the prideful must carry huge stones on their backs to bend them low in a humble manner; the gluttonous must climb without food or water, thereby suffering excruciating hunger; and the lustful must ascend through hot flames to purge themselves of passion’s heat.” He paused. “But before you are permitted the great privilege of climbing this mountain and purging your sins, you must speak to this individual.”

Langdon switched slides to a close-up of the Michelino painting, wherein a winged angel sat on a throne at the foot of Mount Purgatory. At the angel’s feet, a line of penitent sinners awaited admittance to the upward path. Strangely, the angel was wielding a long sword, the point of which he seemed to be stabbing into the face of the first person in line.

“Who knows,” Langdon called out, “what this angel is doing?”

“Stabbing someone in the head?” a voice ventured.

“Nope.”

Another voice. “Stabbing someone in the eye?”

Langdon shook his head. “Anyone else?”

A voice way in the back spoke firmly. “Writing on his forehead.”

Langdon smiled. “It appears someone back there knows his Dante.” He motioned again to the painting. “I realize it looks like the angel is stabbing this poor fellow in the forehead, but he is not. According to Dante’s text, the angel who guards purgatory uses the tip of his sword to write something on his visitors’ foreheads before they enter. ‘And what does he write?’ you ask.”

Langdon paused for effect. “Strangely, he writes a single letter … which is repeated seven times. Does anyone know what letter the angel writes seven times on Dante’s forehead?”

“P!” shouted a voice in the crowd.

Langdon smiled. “Yes. The letter P. This P signifies peccatum—the Latin word for ‘sin.’ And the fact that it is written seven times is symbolic of the Septem Peccata Mortalia, also known as—”

“The Seven Deadly Sins!” someone else shouted.

“Bingo. And so, only by ascending through each level of purgatory can you atone for your sins. With each new level that you ascend, an angel cleanses one of the Ps from your forehead until you reach the top, arriving with your brow cleansed of the seven Ps … and your soul purged of all sin.” He winked. “The place is called purgatory for a reason.”

Langdon emerged from his thoughts to see Sienna staring at him over the baptismal font. “The seven Ps?” she said, pulling him back to the present and motioning down to Dante’s death mask. “You say it’s a message? Telling us what to do?”

Langdon quickly explained Dante’s vision of Mount Purgatory, the Ps representing the Seven Deadly Sins, and the process of cleansing them from the forehead.

“Obviously,” Langdon concluded, “Bertrand Zobrist, as the Dante fanatic that he was, would be familiar with the seven Ps and the process of cleansing them from the forehead as a means of moving forward toward paradise.”

Sienna looked doubtful. “You think Bertrand Zobrist put those Ps on the mask because he wants us to … literally wipe them off the death mask? That’s what you think we’re supposed to do?”

“I realize it’s—”

“Robert, even if we wipe off the letters, how does that help us?! We’ll just end up with a totally blank mask.”

“Maybe.” Langdon offered a hopeful grin. “Maybe not. I think there’s more there than meets the eye.” He motioned down to the mask. “Remember how I told you that the back of the mask was lighter in color because of uneven aging?”

“Yes.”

“I may have been wrong,” he said. “The color difference seems too stark to be aging, and the texture of the back has teeth.”

“Teeth?”

Langdon showed her that the texture on the back was far rougher than that of the front … and also far grittier, like sandpaper. “In the art world, this rough texture is called teeth, and painters prefer to paint on a surface that has teeth because the paint sticks to it better.”

“I’m not following.”

Langdon smiled. “Do you know what gesso is?”

“Sure, painters use it to prime canvases and—” She stopped short, his meaning apparently registering.

“Exactly,” Langdon said. “They use gesso to create a clean white toothy surface, and sometimes to cover up unwanted paintings if they want to reuse a canvas.”

Now Sienna looked excited. “And you think maybe Zobrist covered the back of the death mask with gesso?”

“It would explain the teeth and the lighter color. It also might explain why he would want us to wipe off the seven Ps.”