Hadrian, a new emperor forty years old, had formulated a new policy. He was intent on abandoning Trajan's expensively won territories and drawing the empire back into a shell bounded where possible by 'natural frontiers': deserts, rivers. And where necessary such frontiers would be fortified.

As Brigonius thought this over the more it seemed a remarkable ambition, for to succeed Hadrian was going to have to reshape the Roman spirit. No longer expansive conquerors, the Romans would have to turn their empire into a community. Even the army would have to be redesigned, turned from a mobile fighting force to one able to defend fixed frontiers.

'Of course he has his opponents,' Xander muttered. 'There are plenty of generals who would like their turn at the booty-gathering of the past. Critics in the Senate say that to sit behind a wall and jab at your unconquered enemies with a spear isn't the Roman way-but half of them are fools who still dream of the Republic, and scarcely matter. There are some who wonder if, by halting the expansion that has always fuelled Rome's economy, Hadrian isn't committing some drastic, long-term error-although no doubt we'll all be dead before anybody can answer that.'

Karus said, 'Admirably summarised, architect. But as far as we're concerned, Hadrian's dilemma boils down to this. If you're not going to expand then you have to stabilise the frontiers.'

With typical Roman magnificence, Hadrian intended to consolidate his northern provinces' frontiers into a single defensive boundary, a system of forts, walls, banks and ditches that would span Europe, heading west from Asia Minor, following the great continent-draining rivers to pass north of Dacia, Noricum and Lower Germany-and then it would leap across the Ocean to Britain.

'I think it's clear enough where the British boundary is to be,' Karus said. 'To the north of here, in the place where the neck of the country narrows, between the estuaries of the rivers Tinea and Ituna.'

'Very well,' said Severa. 'The question is what will he build there? We can show him all the models and plans we like. But what will convince this man that he must build in stone rather than turf as he did in Germany?'

Karus said, 'The emperors have been building linear defences of one sort or another since the time of Domitian.'

'Oh, we mustn't mention that,' Xander said. 'Every emperor likes to believe he has built the whole world single-handed.'

Brigonius popped a harmless-looking bit of meat into his mouth. 'Well, don't ask me. I doubt if I'll understand anything anyhow. Haven't you noticed-aside from us, everybody here is speaking Greek!'

Karus grunted. 'And an archaic form at that. How pretentious!'

'It's to please the Emperor,' Xander said. 'His own family are from the provinces, you know. Like all those born most humbly he has the highest aspirations, and so has decided he is a devoted admirer of all things Greek.' Brigonius thought this pompous little man spoke of an emperor as if he was an irritating schoolboy.

'Well,' Brigonius said, 'in that case it's a shame the Greeks didn't build walls of stone, for surely Hadrian would copy them.'

Karus slapped his forehead. 'May Jupiter bugger me but they did! Didn't they, Xander? You should know, man!'

Xander, wide-eyed now, nodded. 'Of course, of course.'

Karus grinned and gripped Brigonius's arm. 'My friend, I think you may have just won us the contest.'

Severa's gaze flickered suspiciously between lawyer and architect. 'You two had better be sure you know what you're doing.'

Xander was flustered, but Karus grinned, a lawyer's smile. 'Trust me.'

And now time ran out, whether Severa trusted Karus or not. Trumpets sounded, a clear peal above the babble. All heads turned to see the former slave Primigenius standing at the door, beside a beaming Marcus Claudius Verecundus, the host. Primigenius called, 'Stand for Publius Aelius Hadrianus.'

And the Emperor walked into the room.

Hadrian gave a brief, gracious speech of welcome, then bade everybody sit and continue with the meal. After a decent interval little groups of citizens approached him with their requests, petitions, disputes to be resolved, or paeans of praise. Severa's party waited their turn.

Brigonius watched the Emperor, fascinated. Hadrian sat with his courtiers, talking animatedly, perhaps about the hunt they had just come from. Hadrian, a heavy-set man, wore a toga, but his face was flushed, his thick hair damp from sweat, and his breathing was heavy.

He immediately struck Brigonius as a mass of contradictions. It was clear that he wanted to seem accessible, but his entrance couldn't have been more dramatic if he had rode in on his horse. He aspired to Greek culture, and yet he exuded the primordial thrill of the hunt. He was the richest man in the world, the very quintessence of Rome-and yet he wore a barbarian beard whose magnificence Brigonius envied. His skin was pocked by the scars of some disease: another contradiction, that the most powerful of all should be afflicted by a disease which could strike down the commonest of people.

And though there was none more powerful than Hadrian there was a fearful look in his eyes, an almost hunted look.

'Yes, a complicated man,' Severa whispered, gazing at the Emperor. 'Talking of the future, I think Hadrian fears it-and not just the assassin's blade. He is a scholar who knows that history holds dire warnings for the Romans, for empires have come and gone in the past: even mighty Alexander's realm barely outlived his own death. Take this business of the Jewish rebellion under Trajan-barely heard of in Britain, but a dreadful disaster in the east. The Jews won't become Romans, as we Britons have; it is a clash of minds, a shuddering shock for the Romans. For all Xander sneers at Hadrian's Greekness, I think it is necessary, a matter of policy as much as personality. He embodies the identity of the empire, which is Greek and Roman, and so in the face of the challenge of the Jews he must be more Greek than the Greeks.

'No wonder Hadrian is obsessed by the future even more than by the past. Everywhere he goes he consults astrologers and mystics and soothsayers. And surely a thoughtful man like Hadrian wants to leave a mark on his empire, on history. What else can assure his own worth in the afterlife?'

Karus's eyes glittered as he listened. 'Isn't she marvellous?' he whispered to Brigonius. 'I told you, it's as if she stands outside time itself.'

Lepidina said, 'Poor man.'

Brigonius asked, 'Who?'

'The Emperor. If he really is so tortured. He might draw comfort if he followed the teaching of the Christ. Because then he would understand that cities and empires don't matter. They all pass away, even Rome. But the city of God endures for ever.'

Severa glared at her. 'That Judean renegade promised that all would be saved, not just emperors but slaves too. What use is that to anybody? Now shut up about your foolish fad, Lepidina.'

'It's not foolish,' Lepidina shot back. 'If it was, why is our Prophecy connected to it? Even the Emperor Claudius noticed that Nectovelin was born in the same year as the Judean!'

'You never mind the Emperor Claudius. I'm your mother and I'm telling you that our family destiny has nothing to do with some ragged-arsed troublemaker from the east. And what's more-'

'Hush,' Xander said. 'We're being called forward.'

'About time,' Karus muttered. 'I'm bursting with piss.'

The five of them advanced towards the imperial table, Severa, Lepidina, Karus and Brigonius, with a nervous Xander supervising two sweating slaves who carried his model on a slab of wood.