And he looked at Lepidina. He couldn't help it.

She was sitting quietly, head down, her hands folded around a half-empty cup of blood-red wine. A year under her mother's thumb in northern forts had not been good for this city girl, and there was no sign of the bright spirit she had shown during that first visit to Camulodunum. She was a bird in a cage of stone.

Karus seemed aware of the glum silence between them. As the conversation about the practicalities of mile-forts ran down, the lawyer lumbered across to Lepidina, sat down, and let the slave boy fill his cup. 'So,' he said, 'how's your marvellous mother? I don't see so much of her these days.'

'Nor do I,' Lepidina said. 'She's too busy writing letters to the governor.'

'Yes, I know about those,' Tullio rumbled, looking up from his discussion. 'Full of nothing but good news. She leaves me to tell him the truth, which always looks bad by comparison.' He sighed noisily. 'That wretched woman!'

Karus said, 'She's a difficult friend-but I wouldn't want her as an enemy.'

Xander asked, 'And how is she feeling about her precious Prophecy, now it is failing to come true?'

Lepidina shrugged. Karus glanced uncomfortably at the soldiers. Brigonius knew that to the Romans prophecies, auguries, divinations and the like were seen as sources of power-and, particularly under an emperor obsessed with his own destiny, you had to be careful. But Severa and her family Prophecy had become the talk of the Wall, and much mocked.

Annius said in his chirpy way, 'Funny thing about that Prophecy. It actually says Hadrian would come to Britain and build a Wall, doesn't it?'

'Not quite,' Lepidina said, 'but close enough.'

'I never heard of a prophecy so, so, what's the word? Specific. Did you, Tull? Usually it's a business of poking around with leaves and entrails and getting a few portents of doom that could mean anything. This is different. It's not like the gods are setting us their usual puzzles. It's more like a man is speaking to us. It's as if somebody in the future knew what was going to happen, wrote it down and sent it back into the past.'

Lepidina said, 'My mother calls him "the Weaver"-or her-the author of the Prophecy.'

'Ah,' Xander said, intrigued. 'But is that possible in any of our philosophies? Do we allow even the gods to know the future-or to change the past?'

Karus said dryly, 'If the legionaries hadn't nailed them all to their sacred trees on Mona it would be interesting to ask a druidh such a question. I know they spoke of a continual exchange of spirits between our world and the Other, but each of our spirits is embedded in time. So I think questions of the existence of the future, or meddling with the past, would be meaningless to them.'

'But in Greece,' said Xander loftily, 'rather more sophisticated notions have been developed.'

'Here we go,' Tullio growled. 'More "sophisticated" horse crap.' He snapped his fingers to have the boy refill their cups.

Xander went on, unperturbed, 'For instance there is the notion of the Eternal Return, in which time is cyclic, and every event is doomed to recur over and again, without limit. This troubled Aristotle, who wondered about causality in a universe in which he existed as much after the fall of Troy as before it. But I suppose you could indeed influence the "past" by ensuring a message about it lasted long enough to reach its recurrence in the "future"…'

'And what about eternity?' Karus cried, sounding a little drunk. 'I thought you Greeks had plenty to say about that, Xander.'

'And some Romans,' Xander said mildly. 'Eternity: a mode of existence in which all events, past and future, coexist. Lucretius argued that duration is a mere product of the mind, for eternity is the higher reality through which we move, you see, and motion gives the impression of change. But of course Lucretius was merely developing older ideas of the Epicureans. And Plato long ago said that our perception of time is a "moving image of eternity", again foreshadowing Lucretius-'

Brigonius struggled to understand this. 'So eternity is like-like what?'

Karus said, 'Brigonius, think of a tapestry. Woven into it are pictures of trees, say, all in their different stages of growth: seeds, saplings, young, mature, old, fallen, decayed away. They are all there all at the same time in the weave, you see. Now, you are an ant running along one thread in the tapestry. And as you run you let your eyes slide over the pictures of the young trees and the old, and you connect them up in your head-and instead of seeing many trees of different ages, you imagine you see only one tree, growing and dying and rotting away. You see? A moving image derived from stasis, passing time derived from eternity.'

Brigonius frowned. 'I think I follow.'

Annius asked, 'So does all this mean that the future can speak to the past?'

Karus laughed. 'If you ask the right question of the right god, perhaps it can! Perhaps time really is a tapestry, its threads all our lives. And somewhere there really is a Weaver, god or man, who sees all, past and future in a glance-and who can, with a few deft plucks, change the pattern of the weave, adjust history, and alter all our lives. But there is always the question of purpose. If the Weaver seeks to perturb history-why, and to what end?'

None of them had an answer to this.

Tullio made an obvious and kindly effort to include Lepidina. 'What of your Christian god, lady? What does He have to say about time and destiny?'

Lepidina said mildly, 'Jesus was God made human. What He had to say to us concerns the way we live our lives. The way we think about each other. He had nothing to say about philosophies of time.'

Karus said, 'Ah, but if I understand your mythology right, Jesus's own life was time-bound, unlike the gods of the past, and it marked a great disjunction in history. He was the God made man, and in His life and His murder He redeemed mankind.'

Xander raised his eyebrows. 'So Jesus is an intervening god, like the gods of Olympus of old. I thought we were done with them! And He was murdered? How?'

'By the Romans,' Lepidina said. 'The governor of Judea had Him put down as a rebel.'

Tullio said gruffly, 'I knew a man, who knew a man, who knew your Christ.'

Lepidina's eyes widened. 'You did?'

'This fellow I'm talking about was a veteran, retired, when I was starting out myself. I was eighteen or so. I met him in Pannonia. And he told me about a veteran he had met when he was young, in Africa. This chap had been a centurion, and he was on duty that day in Judea, when your Christ was crucified. The lads showed Him mercy, he said. As He was dying on the cross, one of them gave Him soldiers' wine.' He raised his cup. 'Just like this.'

They sat gravely, reflecting on this.

Karus murmured, ' "Whilst God-as-babe has birth…" '

'From the Prophecy,' Brigonius said.

'Yes. Lepidina, I've often wondered about the meaning of that phrase. Even if you accept that Severa is right that the text of those lines is about Hadrian and the Wall, that phrase doesn't fit. You have always said the Prophecy is bound up with your young faith because of the coincidence of the birth dates of your ancestor and your Christ. I wonder if that line is telling us something of a great conflict to come, between your young god and the old. But if so, what is the Prophecy guiding us to do? What does the Weaver want?-'

There was a crash, and a smell of smoke. Tullio dropped his cup of wine and ran out of the tent.