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.’