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.”
Sienna looked puzzled by this last point.
“Smell this,” Langdon said, raising the mask to her face like a priest offering Communion.
Sienna cringed. “Gesso smells like a wet dog?”
“Not all gesso. Regular gesso smells like chalk. Wet dog is acrylic gesso.”
“Meaning …?”
“Meaning it’s water soluble.”
Sienna cocked her head, and Langdon could sense the wheels turning. She shifted her gaze slowly to the mask and then suddenly back to Langdon, her eyes wide. “You think there’s something under the gesso?”