Langdon motioned to his right, past the columns, across St. Mark’s Square. “If we get separated, meet at the front door of the basilica.”

The others agreed and quickly began skirting the edges of the crowd and following the western wall of the Doge’s Palace into the square. Despite the laws forbidding feeding them, the celebrated pigeons of Venice appeared to be alive and well, some pecking about at the feet of the crowds and others swooping into the outdoor cafés to pillage unprotected bread baskets and torment the tuxedoed waiters.

This grand piazza, unlike most in Europe, was shaped not in the form of a square but rather in that of the letter L. The shorter leg—known as the piazzetta—connected the ocean to St. Mark’s Basilica. Up ahead, the square took a ninety-degree left turn into its larger leg, which ran from the basilica toward the Museo Correr. Strangely, rather than being rectilinear, the square was an irregular trapezoid, narrowing substantially at one end. This fun-house-type illusion made the piazza look far longer than it was, an effect that was accentuated by the grid of tiles whose patterns outlined the original stalls of fifteenth-century street merchants.

As Langdon continued on toward the elbow of the square, he could see, directly ahead in the distance, the shimmering blue glass dial of the St. Mark’s Clock Tower—the same astronomical clock through which James Bond had thrown a villain in the film Moonraker.

It was not until this moment, as he entered the sheltered square, that Langdon could fully appreciate this city’s most unique offering.

Sound.

With virtually no cars or motorized vehicles of any kind, Venice enjoyed a blissful absence of the usual civic traffic, subways, and sirens, leaving sonic space for the distinctly unmechanical tapestry of human voices, cooing pigeons, and lilting violins serenading patrons at the outdoor cafés. Venice sounded like no other metropolitan center in the world.

As the late-afternoon sun streamed into St. Mark’s from the west, casting long shadows across the tiled square, Langdon glanced up at the towering spire of the campanile, which rose high over the square and dominated the ancient Venetian skyline. The upper loggia of the tower was packed with hundreds of people. Even the mere thought of being up there made him shiver, and he put his head back down and continued through the sea of humanity.

Sienna could easily have kept up with Langdon, but Ferris was lagging behind, and Sienna had decided to split the difference in order to keep both men in sight. Now, however, as the distance between them grew more pronounced, she looked back impatiently. Ferris pointed to his chest, indicating he was winded, and motioned for her to go on ahead.

Sienna complied, moving quickly after Langdon and losing sight of Ferris. Yet as she wove her way through the crowd, a nagging feeling held her back—the strange suspicion that Ferris was lagging behind intentionally … as if he were trying to put distance between them.

Having learned long ago to trust her instincts, Sienna ducked into an alcove and looked out from the shadows, scanning the crowd behind her and looking for Ferris.

Where did he go?!

It was as if he were no longer even trying to follow them. Sienna studied the faces in the crowd, and finally she saw him. To her surprise, Ferris had stopped and was crouched low, typing into his phone.

The same phone he told me had a dead battery.

A visceral fear gripped her, and again she knew she should trust it.

He lied to me on the train.

As Sienna watched him, she tried to imagine what he was doing. Secretly texting someone? Researching behind her back? Trying to solve the mystery of Zobrist’s poem before Langdon and Sienna could do so?

Whatever his rationale, he had blatantly lied to her.

I can’t trust him.

Sienna wondered if she should storm over and confront him, but she quickly decided to slip back into the crowd before he spotted her. She headed again toward the basilica, searching for Langdon. I’ve got to warn him not to reveal anything else to Ferris.

She was only fifty yards from the basilica when she felt a strong hand tugging on her sweater from behind.

She spun around and found herself face-to-face with Ferris.

The man with the rash was panting heavily, clearly having dashed through the mob to catch up with her. There was a frantic quality about him that Sienna hadn’t seen before.

“Sorry,” he said, barely able to breathe. “I got lost in the crowd.”

The instant Sienna looked in his eyes, she knew.

He’s hiding something.

When Langdon arrived in front of St. Mark’s Basilica, he was surprised to discover that his two companions were no longer behind him. Also of surprise to Langdon was the absence of a line of tourists waiting to enter the church. Then again, Langdon realized, this was late afternoon in Venice, the hour when most tourists—their energy flagging from heavy lunches of pasta and wine—decided to stroll the piazzas or sip coffee rather than trying to absorb any more history.

Assuming that Sienna and Ferris would be arriving at any moment, Langdon turned his eyes to the entrance of the basilica before him. Sometimes accused of offering “an embarrassing surfeit of ingress,” the building’s lower facade was almost entirely taken up by a phalanx of five recessed entrances whose clustered columns, vaulted archways, and gaping bronze doors arguably made the building, if nothing else, eminently welcoming.

One of Europe’s finest specimens of Byzantine architecture, St. Mark’s had a decidedly soft and whimsical appearance. In contrast to the austere gray towers of Notre-Dame or Chartres, St. Mark’s seemed imposing and yet, somehow, far more down-to-earth. Wider than it was tall, the church was topped by five bulging whitewashed domes that exuded an airy, almost festive appearance, causing more than a few of the guidebooks to compare St. Mark’s to a meringue-topped wedding cake.

High atop the central peak of the church, a slender statue of St. Mark gazed down into the square that bore his name. His feet rested atop a crested arch that was painted midnight blue and dotted with golden stars. Against this colorful backdrop, the golden winged lion of Venice stood as the shimmering mascot of the city.

It was beneath the golden lion, however, that St. Mark’s displayed one of its most famous treasures—four mammoth copper stallions—which at the moment were glinting in the afternoon sun.

The Horses of St. Mark’s.

Poised as if prepared to leap down at any moment into the square, these four priceless stallions—like so many treasures here in Venice—had been pillaged from Constantinople during the Crusades. Another similarly looted work of art was on display beneath the horses at the southwest corner of the church—a purple porphyry carving known as The Tetrarchs. The statue was well known for its missing foot, broken off while it was being plundered from Constantinople in the thirteenth century. Miraculously, in the 1960s, the foot was unearthed in Istanbul. Venice petitioned for the missing piece of statue, but the Turkish authorities replied with a simple message: You stole the statue—we’re keeping our foot.

“Mister, you buy?” a woman’s voice said, drawing Langdon’s gaze downward.

A heavyset Gypsy woman was holding up a tall pole on which hung a collection of Venetian masks. Most were in the popular volto intero style—the stylized full-faced, white masks often worn by women during Carnevale. Her collection also contained some playful half-faced Colombina masks, a few triangle-chinned bautas, and a strapless Moretta. Despite her colorful offerings, though, it was a single, grayish-black mask at the top of the pole that seized Langdon’s attention, its menacing dead eyes seeming to stare directly down at him over a long, beaked nose.

The plague doctor. Langdon averted his eyes, needing no reminder of what he was doing here in Venice.

“You buy?” the Gypsy repeated.

Langdon smiled weakly and shook his head. “Sono molto belle, ma no, grazie.”

As the woman departed, Langdon’s gaze followed the ominous plague mask as it bobbed above the crowd. He sighed heavily and raised his eyes back to the four copper stallions on the second-floor balcony.

In a flash, it hit him.

Langdon felt a sudden rush of elements crashing together—Horses of St. Mark’s, Venetian masks, and pillaged treasures from Constantinople.

“My God,” he whispered. “That’s it!”

CHAPTER 72

Robert Langdon was transfixed.

The Horses of St. Mark’s!

These four magnificent horses—with their regal necks and bold collars—had sparked in Langdon a sudden and unexpected memory, one he now realized held the explanation of a critical element of the mysterious poem printed on Dante’s death mask.

Langdon had once attended a celebrity wedding reception at New Hampshire’s historic Runnymede Farm—home to Kentucky Derby winner Dancer’s Image. As part of the lavish entertainment, the guests were treated to a performance by the prominent equine theatrical troupe Behind the Mask—a stunning spectacle in which riders performed in dazzling Venetian costumes with their faces hidden behind volto intero masks. The troupe’s jet-black Friesian mounts were the largest horses Langdon had ever seen. Colossal in stature, these stunning animals thundered across the field in a blur of rippling muscles, feathered hooves, and three-foot manes flowing wildly behind their long, graceful necks.

The beauty of these creatures left such an impression on Langdon that upon returning home, he researched them online, discovering the breed had once been a favorite of medieval kings for use as warhorses and had been brought back from the brink of extinction in recent years. Originally known as Equus robustus, the breed’s modern name, Friesian, was a tribute to their homeland of Friesland, the Dutch province that was the birthplace of the brilliant graphic artist M. C. Escher.

As it turned out, the powerful bodies of the early Friesian horses had inspired the robust aesthetic of the Horses of St. Mark’s in Venice. According to the Web site, the Horses of St. Mark’s were so beautiful that they had become “history’s most frequently stolen pieces of art.”

Langdon had always believed that this dubious honor belonged to the Ghent Altarpiece and paid a quick visit to the ARCA Web site to confirm his theory. The Association for Research into Crimes Against Art offered no definitive ranking, but they did offer a concise history of the sculptures’ troubled life as a target of pillage and plunder.

The four copper horses had been cast in the fourth century by an unknown Greek sculptor on the island of Chios, where they remained until Theodosius II whisked them off to Constantinople for display at the Hippodrome. Then, during the Fourth Crusade, when Venetian forces sacked Constantinople, the ruling doge demanded the four precious statues be transported via ship all the way back to Venice, a nearly impossible feat because of their size and weight. The horses arrived in Venice in 1254, and were installed in front of the facade of St. Mark’s Cathedral.

More than half a millennium later, in 1797, Napoleon conquered Venice and took the horses for himself. They were transported to Paris and prominently displayed atop the Arc de Triomphe. Finally, in 1815, following Napoleon’s defeat at Waterloo and his exile, the horses were winched down from the Arc de Triomphe and shipped on a barge back to Venice, where they were reinstalled on the front balcony of St. Mark’s Basilica.

Although Langdon had been fairly familiar with the history of the horses, the ARCA site contained a passage that startled him.

The decorative collars were added to the horses’ necks in 1204 by the Venetians to conceal where the heads had been severed to facilitate their transportation by ship from Constantinople to Venice.

The doge ordered the heads cut off the Horses of St. Mark’s? It seemed unthinkable to Langdon.

“Robert?!” Sienna’s voice was calling.

Langdon emerged from his thoughts, turning to see Sienna pushing her way through the crowd with Ferris close at her side.

“The horses in the poem!” Langdon shouted excitedly. “I figured it out!”

“What?” Sienna looked confused.

“We’re looking for a treacherous doge who severed the heads from horses!”

“Yes?”

“The poem isn’t referring to live horses.” Langdon pointed high on the facade of St. Mark’s, where a shaft of bright sun was illuminating the four copper statues. “It’s referring to those horses!”

CHAPTER 73

On board The Mendacium, Dr. Elizabeth Sinskey’s hands were trembling. She watched the video in the provost’s study, and although she had seen some terrifying things in her life, this inexplicable movie that Bertrand Zobrist had made before his suicide left her feeling as cold as death.

On the screen before her, the shadow of a beaked face wavered, projected on the dripping wall of an underground cavern. The silhouette continued speaking, proudly describing his masterpiece—the creation called Inferno—which would save the world by culling the population.

God save us, Sinskey thought. “We must …” she said, her voice quavering. “We must find that underground location. It may not be too late.”

“Keep watching,” the provost replied. “It gets stranger.”

Suddenly the shadow of the mask grew larger on the wet wall, looming hugely before her, until a figure stepped suddenly into the frame.

Holy shit.

Sinskey was staring at a fully outfitted plague doctor—complete with the black cloak and chilling beaked mask. The plague doctor was walking directly toward the camera, his mask filling the entire screen to terrifying effect.

“ ‘The darkest places in hell,’ ” he whispered, “ ‘are reserved for those who maintain their neutrality in times of moral crisis.’ ”

Sinskey felt goose bumps on her neck. It was the same quotation that Zobrist had left for her at the airline counter when she had eluded him in New York a year ago.

“I know,” the plague doctor continued, “that there are those who call me monster.” He paused, and Sinskey sensed his words were directed at her. “I know there are those who think me a heartless beast who hides behind a mask.” He paused again, stepping closer still to the camera. “But I am not faceless. Nor am I heartless.”