There were strikingly many circular structures: the houses, ditches and banks, rings of standing stones which for all he knew they might have been forts, or temples, or simply places to keep the sheep. It struck him that as seen from the air, by a curious crow perhaps, Britain would be covered by circles, like a muddy field splashed by rain.

But Romans built in straight lines, and the new military road would cut through this landscape of circles, rude as a sword slash. Roman roads ran straight for long stretches because they were designed to support army marches, and as long as they had a good surface and sound drainage and weren't too steep for a soldier loaded with his kit, the roads could be laid across almost any landscape.

Narcissus knew that such stupendous rectilinearity was itself an oppressive marker of Roman dominance. This was a land beyond the Ocean, a land at the very edge of the Roman mind, beyond which lay madness. But here was the army to impose order on chaos.

That was the theory. But, he reflected, this 'chaos' was a place of neat little fields and farmhouses. He murmured, 'We are here to civilise the moon. But there is a civilisation here already!'

'Peaceful, too,' Vespasian murmured. 'Those low walls are for keeping out sheep, not men.'

'Caesar wrote of waves of invaders from the continent. It's true you see pots from Germany and brooches from Gaul. That doesn't mean the potters and jewellers came over in force! Julius wanted to make Britain seem the wilder place, I suppose, and his own deeds the greater by association. Yet I should have anticipated this,' he said. 'After all it is deliberate policy to cultivate our neighbours.'

In return for high-quality goods from the empire, raw materials were imported from Britain: minerals, wheat, leather, minerals, hunting dogs-and, increasingly in the last few decades, slaves, though as Narcissus could testify from his personal experience Britons made for testy servants. The empire made a fat profit on such trade, trinkets exchanged for huge volumes of raw materials. Narcissus, a thoughtful man, considered this pattern probably inevitable when an advanced culture dealt with a more primitive one. And all of this served the longer term goals of the empire. Roman material culture was an invaluable tool for manipulating local elites, and friendly native rulers provided an inexpensive buffer against more remote barbarians.

'So we have tamed these southern Britons. I just didn't expect to see it had gone this far.' Narcissus felt somehow irritated by the landscape's lack of strangeness.

'Perhaps it has gone further than you think,' Vespasian said. He produced a coin, roughly cut and stamped. 'This was part of a hoard, a tribute for Aulus Plautius from the ruler of a local mud-heap. The coin was issued by the king of the Atrebates, in fact-our friend Verica. Yes, the British strike their own coins! Or at least some of them do.'

Narcissus took the coin. 'It's gold.'

'Yes. Used for tribute, it seems, not for commerce, for it has too high a value. Even these half-civilised Britons don't get the point of a currency, it seems.

'But we still know little of what lies beyond this south-east corner. We believe there are more than twenty tribes out there, of which we have made serious contact with only a handful. No doubt there are plenty of hairy-arsed fellows out there in the hills who have never even heard of a Roman.'

Still Narcissus felt faintly uneasy. 'But this is a land with its own story. You can see that, just by looking from here. And now here we are to wipe it all away. You know, when you occupy a country you take on the responsibility for its people, perhaps millions of them, for all their hopes and dreams. I sometimes wonder if Rome knows the gravity of what it is doing.'

Vespasian looked at Narcissus curiously. 'You aren't feeling a prick of conscience, are you, secretary?'

'Every thoughtful man has a conscience.'

'The Britons are farmers, but nothing more. You can buy a woman with a handful of glass beads, and her husband with a mirror so he can comb his scraggly beard-but he will be frightened by the barbarian looking back out at him! We must be like parents with these child-like people. Firm but fair.'

'Oh, I understand that.' Narcissus shook off his mood, reminding himself it was always a mistake to show the merest chink of weakness-always. He took one last glance back at the landscape. 'By Apollo's eyes I couldn't bear to live in one of those wooden huts. They sit there like huge brown turds. No wonder the Britons are dazzled by a goblet of wine or two!'

Vespasian laughed, and led the way down the slope.

Agrippina lay on her belly in the low brush. She had been here since first light. She was stiff, her neck was sore, and she was out of food and low on water. But here she lay, silent and motionless, her face blackened by dirt, for she was spying on the Roman army.

Even she, educated in Gaul, had been stunned to see a Roman army on the march close up. The tens of thousands of men in close order had taken no less than three hours, she estimated, to stream past her position. All that time the noise had been deafening. The Romans awed her, even as she clung to her shard of hatred over Mandubracius, and her longing for revenge.

But she kept her mind clear. She had tried to count the troops and units, baggage carts and animals. She had already sent preliminary information by a runner to the camp Caratacus had established to the west of here, on the bank of the River of the Cantiaci. Despite the princes' warlike bluster, for now they had followed Nectovelin's advice, to watch, to gather information on the Romans, and to strike at them in small corrosive ways. Thus Agrippina was just one of a network of spies across the country.

After the main body of the force passed she kept her station, to see what might follow. She was given a lesson in Roman road engineering.

It had begun even before the first soldiers had come this way. Surveyors, protected by a detachment of cavalry, took up positions on ridges and hills. They had mysterious contraptions of wood and string and lead weights that they held up before their faces. Agrippina imagined this must have something to do with making sure the road ran straight. After that the route was marked out with canes thrust into the ground every few paces, and the surveyors hurried on to their next station.

After the main force of the army had passed along the marked-out route a construction gang followed. The gang themselves seemed to be soldiers; a cart followed with armour and weaponry piled high, though every man kept a knife at his belt.

They worked their way along a track already churned up by forty thousand pairs of boots, tens of thousands of hooves. First they cleared the central track of undergrowth, and then dug out ditches to either side, heaping up the dirt along the spine of the road. They piled large, heavy rocks on top of the ridge of dirt, and then a layer of smaller rocks, and finally gravel was shovelled out and spread crudely. The smaller rocks and gravel were hauled along in carts, but the heavy rocks were scavenged locally-mostly from the dry stone walls of local farms, but there were no farmers around to complain. At last the soldier-engineers walked up and down along the newly laid stretch of the road, ramming down the gravel with heavy posts.

As the soldiers worked, under the pleasantly warm British sun, they sang. Many of their work-songs were in Latin, but Agrippina recognised some Gallic, and even a little Germanic. Rome's soldiers did not only come from Rome these days.

Agrippina had seen Gaul; she knew what the future would hold. From this beginning the roads would spread out across the country like ivy over a wall, bifurcating and firing off their straight-line segments, until every corner of the land was reached. Messages would flash along the roads fast as thought, and the next time the soldiers needed to march this way they would be able to make much faster progress than today, through the mud and dirt. And in the future the young fighters of Britain, who today were preparing raids against the advancing Romans, would be marched away along these roads to go fight in Germany and Thrace and Asia, far from the misty cool of their homeland. Thus the empire absorbed its enemies and used them for its own further expansion-