If his research was accurate, then if any scrap of the old Prophecy had survived, it would be in the form of this hapless slave boy. But somehow Thalius had never quite worked out what he would do when faced with the boy himself.

'Let me try,' Tarcho said. He lumbered forward massively, and knelt before the boy. He spoke softly, in a variety of tongues; perhaps one of them was a British dialect, the native tongue of Audax's ancestors, and Thalius's. The boy didn't look up, but at least he didn't flinch as he had from Thalius.

Nodding reassuringly, the old soldier took the boy's left hand and then the right, inspecting the palms and nails. He ran his hands along the boy's arms and legs, and brushed through the boy's matted hair-Thalius could see lice squirming-looked into his mouth, and ran a hand over his belly and back. It was a brisk inspection he might give a dog. The boy had evidently been through this sort of thing before and submitted passively.

Then Tarcho turned the boy around and lifted up the rag that served him as a tunic. 'Thalius. I think you'd better come see this.'

Thalius stepped forward. The boy's bare back was a mass of purple-red scarring. Thalius recoiled in disgust and turned on Volisios. 'He has been beaten, and savagely by the looks of it.'

Volisios glared back. 'If he has it's nothing to do with me.'

'No,' Tarcho said firmly. 'Thalius, look again. These are not the marks of a whip. See this circle, the curve here.'

The marks crudely etched into the boy's flesh were letters: Latin letters, roughly arranged in a square array.

As they stared, the boy turned his head, a spark of curiosity showing in his eyes for the first time since he had been brought here. Thalius wondered if he even knew he had been carrying around a message inscribed on his back, perhaps all his life.

Thalius was profoundly relieved to get back above ground, even if the climb left him winded.

Volisios escorted Thalius and Tarcho to his site office, a mudbrick block a little better appointed than the rest of the shacks here. Tarcho took the boy away to clean him up and inspect him a bit more closely. Thalius was happy to leave the boy in Tarcho's hands. Tarcho was no doctor but he had commanded soldiers in the field, and knew a little basic anatomy and medicine.

While he waited Thalius wanted only to rest, too exhausted even to speak. Respecting this, Volisios served Thalius with some watered-down wine, a rather rough British-grown vintage, and turned to some paperwork.

Thalius reflected on how lucky he was to have Tarcho's support. Tarcho was in his fifties, about the same age as Thalius himself, but a greater contrast between the two men was hard to imagine. Thalius was a man of property and business. He ran a pottery partnership, selling cups and plates to the army. It was a business that had been in the family for generations. He wasn't as rich as he might have been, however, for he had also inherited his father's position on the Camulodunum town council, the curia. His responsibilities for tax collection, upkeep of the town walls and other civic duties were onerous and expensive-which was, of course, why they had been made compulsory and hereditary.

By contrast Tarcho, descended from a long line of soldiers of German origin, was a pillar of a man, calm, solid and stolid, with a ferocious crimson beard now laced with grey. He had served most of his twenty-five years in a garrison on Britain's eastern shore-though some of those years had been accumulated under the reign of Carausias, the notorious usurper. It had been a pragmatic gesture by Constantius Chlorus, leader of the great Roman Invasion of Britain nearly twenty years ago, to have decreed that if soldiers like Tarcho were prepared to switch sides, their service under Carausias would count towards their retirement privileges.

But what was a retired Tarcho to do? He was unmarried. He was too restless to farm, and too scrupulous to serve as some tax collector's hired thug. So he had come to Camulodunum looking for more suitable work, and through friends of friends had run into Thalius, who had been on the look-out for a dependable bodyguard. Thalius had certainly been glad of his company as he had ventured out of the safety of Camulodunum's walls and made this journey to the far west, travelling through one of the four British provinces and into another.

A contrasting pair they might have been, but Tarcho had become a right-hand man to Thalius, a sounding board as much as protective muscle. Both childless bachelors, their company was congenial. And they were united, and divided, by a shared religion: Christianity. On their travels the two of them had had long and interesting debates on the nature of the faith. But then, as Volisios had remarked, everybody was a theologian nowadays.

Tarcho's expressions of his tough creed had actually crystallised for Thalius his own doubts about the new Emperor, and the direction he was taking the faith. It was these doubts, in fact, which had brought Thalius to this mine-and what he hoped to achieve here was but a step towards his own ultimate goal, a confrontation over the direction of Christianity with the Emperor himself.

Christianity was a long-standing passion within Thalius's family, said to go back centuries to Lepidina daughter of Severa, who had lived not long after the death of Christ Himself. Thalius's faith was of an old-fashioned sort, a faith of love and hope, his community united in charitable associations of mutual aid-a faith derived from the teachings of Christ Himself, Thalius liked to believe. Tarcho, though, was a Christian of the new type. Like his Emperor's, Tarcho's was a robust soldier's faith, his god a warrior who had proved His mettle by beating off other deities in battle. It was this metamorphosis of Christianity into a military creed he could no longer recognise that Thalius, gravely concerned, had been forced to reject. But the new direction came from the Emperor himself. What was a man of conscience to do?

When he heard that the Emperor was coming to Britain to do some troop-raising, an idea had struck Thalius, a seed planted in his mind. The Emperor would receive audiences-and so why, then, shouldn't Thalius himself be received, and make his doubts known? Any rational ruler would surely accept the ideas and viewpoints of those he aspired to rule. Why not Thalius?

But as soon as he conceived this thrilling idea he was plagued by doubt. Was he taking himself too seriously? Who was he, a member of a mere provincial curia, to comment on imperial policy?

That was when, casting around for a way forward, it occurred to Thalius to turn to the old family story of the Prophecy, the lost poem of the future. It was a forlorn hope that he might recover it, perhaps, but even in these days of bleed-you-white taxes Thalius was prosperous enough to afford to be able to indulge a fascination for family history. And in a time of such uncertainty, if the Prophecy really did contain a glimpse of the true future it was worth a try to find it. With its authority behind him-always assuming the Prophecy existed, and could be found, and was worth presenting-perhaps he would have an excuse to face an emperor and his court, and the courage to do it.

It was spurious, perhaps, and not even very logical, but it was a plan, a strategy, and he had followed it through this far. And after all it was the family story, passed down from long-dead Lepidina, that the Prophecy actually had something to do with the destiny of Christianity. If that was true-if he could decode it and apply its message, if he could relay its truth to the Emperor himself, Thalius told himself with a kind of breathless anticipation-he might do mankind a great service indeed.