He turned to his housekeeper, and called for the boy.

Two days later in the afternoon, Thalius invited Cornelius and Aurelia to his townhouse in Camulodunum. Thalius had arranged for his triclinium, his dining room, to be stocked with food, wine and water, so they need not be disturbed by service. He insisted his guests leave their attendants outside; he sent them off to the kitchen where they would be fed and watered. And he strictly ordered his housekeeper to keep everybody out of the room until he, Thalius, gave instructions otherwise-and that was to include the housekeeper himself.

Cornelius mocked him. 'Oh, Thalius! You are a conspirator after all!'

'No, I am not,' Thalius said coolly. 'But this is an age of spies. I want nobody in the room with us who I don't know and trust.'

Aurelia smiled coldly. 'But you don't know us-and if you trust us you are a fool.'

'But we are already locked together in complicity,' Thalius said. 'You will not betray me for to do so would be to betray yourself. Enlightened self-interest-was that your phrase, madam?'

Cornelius said, 'And the boy, the slave on whom the destiny of an empire pivots?'

'I have sent him to the kitchen with Tarcho-and, incidentally, I have instructed Tarcho to guard the boy as he has guarded me these last eight years.'

Aurelia said, 'Why have you invited us, Thalius? What do you want to achieve today? Have you thought it through that far?'

Cornelius rumbled, 'I doubt if any of us has.'

Thalius said, 'We appear to have a common interest. We may uncover a common goal. Let's leave it at that for now.'

That seemed to satisfy them. For a while, in the closed and locked room, sipping diluted wine, they were silent.

Claudia Brigonia Aurelia lay on her couch. She seemed effortlessly in control, utterly superior. Thalius was sure that the soft crossing of her ankles, the way the drapery of her dress fell about her hips and thighs and hung away from her breasts-none of it was accidental but the product of a lifetime of self-training. With such simple tools she must effortlessly dominate the men around her, even now she was growing old. He thought too of what she had told him of an unrequited love affair between their ancestors, centuries ago. Was it possible that such unsatisfied lusts could send echoes down the generations? But that was a very un-Christian thought, he decided.

Aside from her sexuality he sensed she was a natural snob, and had the manner to go with it; before her judgemental gaze he felt unreasonably ill at ease in his own home. Though her family was no better off than Thalius's, she did have an ancestry she could trace back to the Claudian conquest, the date at which British history began-but she spoke of legends of royal blood even before that. Perhaps her ancestor was a princess of Troy, for the British race was supposed to have been founded by Trojans, who, fleeing the war with the Greeks, had brought the chariots that had met Caesar. It was only as an adult that Thalius had come to challenge this imported Mediterranean legend-and to wonder what true history had been lost, what old remembered wisdom dissipated, when the ancient British nations had been obliterated by Rome.

While Aurelia sat, Cornelius carried a brimming cup of wine and walked around the triclinium, looking at the frescoes and the tapestry. He didn't seem distracted by Aurelia's charms. Perhaps, Thalius wondered, as many of Constantine's eastern-tinged courtiers were rumoured to be, Cornelius preferred to pluck his fruit from a different tree.

Thalius lumbered to his feet, picked up a jug of wine and refreshed their cups. 'In the absence of a servant I must remember my duties as a host. You're taken by that fresco, Ulpius Cornelius?'

This particular painting showed a portrait of Christ at the time of His mission, a smooth-faced man of thirty or so, His hand raised in blessing. The figure was surrounded by symbols: the chi-rho, a sunburst behind Christ's head, and a small acrostic in a lower corner.

'It's done well enough,' Cornelius said, rather patronisingly. 'But Christ was a fisherman in Judea, wasn't he?'

'Actually a carpenter.'

'And a rabble-rouser. He would never have worn a toga!'

Thalius smiled. 'That's what the pattern-book showed, and my artist didn't have the confidence to deviate from the design.'

'Interesting symbolism.' Cornelius tapped the chi-rho with a fingernail. 'I've seen this before.'

Aurelia languidly uncurled from her couch and joined them. 'It's called the Christogram. The first two letters in Christ's name in Greek, superimposed-you see?'

'I have seen this scrawled on temple walls. Even in Rome.'

Thalius said, 'A relic of the days of persecution. Such symbols as this united a community under pressure.'

'But now Christians are under pressure no more,' Cornelius said. 'And your Christogram has become a symbol of pride, yes?'

Aurelia said, 'Ah, but the Christogram is more than that. Look again, Cornelius. Haven't you seen figures rather like this in other contexts?'

Cornelius stepped back and tipped his head. 'Do you know, I have. In Egypt, I think. It is rather like the ankh, an ancient mystic symbol-surely much more ancient than Christianity!'

Aurelia murmured, 'As a girl I learned to write Greek. This is also rather like a sign you make when editing a passage of writing-chi-rho for chreston, which means good.'

'One symbol with many meanings, then,' Cornelius said.

'But that's intentional,' Aurelia said. 'You can scrawl a chi-rho on your wall; a Christian will see the Christogram, a pagan will see an Egyptian good-luck sign. It appeals to everybody and offends nobody. The Emperor's advisers are wily to encourage it.

'Constantine is a Christian. Everybody knows that. And he wishes to establish Christianity as the empire's core religion. But almost everybody else of influence-like you, Cornelius!-remains pagan. Most of the army too, despite Constantine being one of its own. Constantine, and the bishops who manipulate him, is proceeding subtly, through tools such as this clever little symbol. But, like the rain beating on your tiles, Cornelius, each drop brings you pagans closer to the day when the roof falls in.'

Thalius said, 'You seem to have thought deeply about this, madam.'

'Emperors make the weather,' she murmured. 'It is best to pay them attention. Besides I am fascinated by the sheer machination of it all.'

Cornelius said, 'Machination, yes. And there are plenty who doubt Constantine's sincerity about his conversion in the first place. How is it even possible for a good pagan to become Christian?'

'Oh, I believe he is sincere,' Aurelia said. 'And as for how he was converted, you can see it painted up here on dear Thalius's wall.'

Cornelius looked again. 'You mean the sunburst around Christ's head?'

Aurelia said, 'Constantine grew up as a protege of Apollo. And some years ago he hailed the sun god, Sol Invictus, as his tutelary god. Some would identify Apollo with the sun, and others identify the sun with your Christ, Thalius: Jesus is sol justitiae, the sun of justice. So you see there is a progression, logical in its way, through an overlapping identity of deities, from Apollo, via the sun, to Christ. But it will be quite a challenge for the biographers to make sense of all this one day.'

Thalius felt irritated at this smug analysis. 'All this theological trickery has nothing to do with the true nature of Christ and His message.'

Aurelia just laughed.

Cornelius turned to Thalius. 'It is a little difficult to understand, good Thalius, what it is you object to about an emperor adopting your own long-marginalised faith.'

'But the faith of Constantine isn't necessarily mine,' Thalius said unhappily. 'Constantine's warrior God has nothing to do with Christ and His teachings. And the Church he is creating is a mirror of the man and his empire: centralised, autocratic, intolerant, ruthless. That is why true Christians are appalled. Many of us are turning away-becoming ascetic, hermits and monks, retreating into the wilderness.'