… is not Antinous, not even a vague approximation. Am I the only one who can see him?”

Hadrian turned his back on the statue, as if disgusted by it.

Apollodora looked desperately at Marcus. “Husband, do it!” she whispered.

“Now is not the time,” he said through clenched teeth.

But Apollodora had staked so much on this meeting that she could not let the chance go by. She rushed to Hadrian, even as he was departing, and dropped to her knees. “Caesar, we have a favour to ask. My father, in Damascus – he longs to return to Roma. If you could forgive him – we beg you!

Hadrian shuddered. He waved his hand dismissively, turned away from her, and walked on.

Following him, Antinous looked over his shoulder and cast a parting glance at the statue. To Marcus, the face of the youth and the face of the statue were mirror images, perfectly alike in every way.

At the doorway to the vestibule, Hadrian stopped and collected himself. He kept his eyes averted. His voice was strained but calm. “You will return to work on the temple, Marcus Pinarius. There is still much you can accomplish there. But you will destroy this abomination, and everything to do with it. Do you understand? As soon as I’m gone, you will destroy every model and burn every drawing. You will break this statue into pieces. You will grind the pieces to dust. No one must ever see it.”

Work continued on the Temple of Venus and Roma – with the huge columns at last in place, the true massiveness of the structure was becoming evident – but on this day Marcus was at work at different site, out on the Field of Mars, where Hadrian had decided to rebuild a neglected ruin called the Pantheon.

The original structure, a temple dedicated to the great gods, had been erected by Agrippa in the reign of Augustus. Damage caused by fire in the reign of Titus had been repaired by Domitian. Another fire, caused by lightning, virtually destroyed the temple while work was under way on Trajan’s Column and Forum, and with those enormous projects claiming all available resources, the rebuilding of the Pantheon was neglected. For almost twenty years the Pantheon remained in ruins, a cordoned-off area in the bustling heart of the Field of Mars. Passing the familiar eyesore one day, Hadrian suddenly saw it afresh. The limitations of the site were such that any rebuilt temple would have to be nearly square in shape. It was hard to imagine an aesthetically pleasing temple no deeper than it was wide – essentially a cube. But what if the rebuilt temple was circular – or indeed, as Hadrian perceived in a flash of inspiration, spherical? Here at last, the emperor realized, was the project to which he could give full expression to his fascination for domes – the “giant gourds” that Apollodorus had derided. The rebuilt Pantheon would be unique, a sphere within a square, surmounted by a dome of almost inconceivable size. The challenge of constructing such a dome had defeated engineers in the past, but Hadrian insisted that it could be done, and had charged Marcus with doing so.

The emperor’s expression of confidence in him had surprised Marcus, who had been badly shaken by Hadrian’s rejection of the statue. But not once had Hadrian ever reminded Marcus of his displeasure on that occasion, and Marcus was determined to show the emperor that his trust was well placed. Fired by Hadrian’s enthusiasm, Marcus and a team of engineers had conceived new ideas for making such a vast dome feasible – making the concrete thinner near the top, using coffers to lessen the mass, and using an oculus, an eye-like opening at the top, to admit light and further reduce the weight. Marcus was determined that his efforts should not disappoint the emperor. He often wished that Apollodorus were with him to offer advice and help oversee such a hazardous but thrilling enterprise.

The actual construction of the dome was still a long way off. On this day, Marcus was inspecting recent work on the thick, load-bearing walls when he heard a familiar cry and looked up to see his son’s blonde curls glinting in the sunlight.

At the age of eight, Lucius was now old enough to visit his father’s worksites, as long as he was always supervised. Marcus was surprised to see that Lucius was accompanied not by one of the slaves who usually chaperoned him but by Amyntas, who had rapidly risen in the ranks of the household and was usually occupied with more-important duties.

Marcus greeted the boy by lifting him in the air – not as easy a task as it once had been – then saw the reason why Amyntas had come. In the slave’s hand was a scroll, and even at a distance Marcus could spot the imperial seal pressed into the wax.

Hadrian was again off travelling. He frequently corresponded with Marcus, but those letters were usually bundled with other imperial documents and delivered by couriers to the palace, where Marcus sent a slave to fetch them. A letter that had come not to the palace but directly to Marcus’s house was unusual.

While Amyntas took Lucius to look at the walls, Marcus broke the seal and unrolled the scroll. Previous letters had come from Sicily, Carthage, the interior African city of Lambaesis, Athens, Ephesus, and Antioch. The heading of this letter showed that it had been posted from the desert trading city of Palmyra. Recalling its close proximity to Damascus, Marcus felt a twinge of hope. Apollodorus in his latest letter had expressed his intention to do his best to gain an audience with Hadrian, should the emperor’s travels bring him anywhere near Damascus.

The letter was written not in Hadrian’s usual first person, full of learned asides and literary allusions, but in a very stiff and formal third person. From the first words, Marcus knew the letter contained bad news:

Caesar wishes to inform Marcus Pinarius personally of an unfortunate event, so that he will hear of it first from Caesar and not from some other source. Caesar will state the fact plainly: the father-in-law of Marcus Pinarius, Apollodorus of Damascus, has been executed for plotting against the life of the emperor. Because of irrefutable evidence supplied to Caesar, Caesar had no other recourse. This action was carried out swiftly and with respect to the person’s status as a citizen.

Marcus knew what that meant: Apollodorus had been beheaded and not killed in some more disgraceful way, like crucifixion.

Marcus Pinarius need fear no recrimination against himself. Although Caesar is aware of the natural bond of affection between Marcus Pinarius and his father-in-law, Caesar is of the belief that Marcus Pinarius played no part whatsoever in the plot, is certain of Marcus Pinarius’s loyalty to the emperor, and desires Marcus Pinarius to continue his valuable work on the Temple of Venus and Roma and on the Pantheon. It is the wish of Caesar that this unfortunate event shall have no effect on the amity between himself and Marcus Pinarius. We shall not speak of it again.

Stunned, Marcus put down the letter. Could it be true that Apollodorus had conspired against the emperor? Had the bitterness of so many years of exile driven him to involve himself in some desperate plot? Hadrian’s journeys exposed him not just to those who sought favours from the emperor but to those in each region who craved revenge, and in the vicinity of Damascus, where so many had been subjected to so much suffering under Roman rule, there must be many such persons. Had Apollodorus conspired with other malcontents and been discovered by Hadrian’s agents? Or had he been the victim of rumors and lies? Hadrian spoke of “irrefutable evidence,” but that phrase was invariably used when a declared enemy of the state was put to death.

Marcus would probably never know the truth. The emperor was above being questioned. Apollodorus was beyond giving answers.

Marcus saw something from the corner of his eye. It took him a moment to realize that it was a man in a toga. Only when the man spoke did he recognize Gaius Suetonius.