Anyhow there were no emperors here now, and the place swarmed with Saxons. Living in clusters of small wooden buildings outside the fort's earthworks these Germans handled the sparse trade from the continent. They used this old fort, built to repel their own piratical ancestors, as a storage depot, and just as in Gaul the only tongues you heard were Germanic.

Isolde and her father found a small timber-built church set on the fort's north-west corner. It had a pretty baptismal font, made of reused red Roman tile. They said prayers of thanks for their safe passage this far. Then they returned to the small wharf and stood together uncertainly while the trader unloaded his boat.

The Saxons looked extraordinary to Isolde. Many of them were blond and blue-eyed. The men shaved the front of their heads and let the hair grow at the back, an effect that made their faces look long, like a wolf's. There were plenty of kids running around the wooden-hut settlement. Perhaps their fathers had been pirates, but these were clearly immigrants and had no plans to go anywhere. But every adult wore a knife at the waist; even some of the older children carried weapons.

Isolde was relieved when a young monk came pushing through the throng to greet them. He dressed as Nennius did, in a plain robe of heavy brown cloth, tied off with a belt of rope. He was young, perhaps not much older than Isolde. But his tonsure, severely cut, looked rather old-fashioned to Isolde, though she was no expert on monkish modes. His name was Damon, he said. 'I bring greetings from the bishop of Camulodunum, and I come to escort you there.'

'Oh, how kind, how thoughtful,' Nennius burbled. 'The exchange of letters I have already enjoyed with Bishop Ambrosius has been delightful, and I am sure the gift of his hospitality will be most welcome…'

Damon guided them to a carriage, crude but covered and serviceable. He had a man with him, a rough-looking servant too surly to be a slave; he hauled the visitors' baggage from the wharf to the cart. Damon went on, 'The bishop asked me to stress that the honour is all his. Any friend of Pelagius is welcome in his palace.'

Nennius nodded. 'Britain has become something of a refuge for we Pelagians, I fear. But then Pelagius was born here; he is one of our own.'

Damon said cautiously, 'Perhaps you haven't heard the most recent news.'

'About Pelagius's excommunication by Pope Zosimus? Quite a victim for Augustine and his crew!'

'Bishop Ambrosius comforts us that truth and goodness will prevail in the end,' Damon said mellifluously.

They walked to the carriage as they talked. Isolde felt tired, bloodless, even a little giddy, but her father was oblivious to her, of course, and so was Damon, the young monk, and nobody helped her.

The Saxons, going about their own business, ignored them as they passed. The shoulder straps of the women's gowns were fixed with brooches, they had sleeve-clasps around their cuffs, and around their waists they wore belts from which dangled odd metal good-luck charms like large keys. Isolde thought the style was rather attractive, and the quality of the metalwork looked good. She wondered if they would stop at any markets where she could do some shopping.

It would take two days' travel to reach Camulodunum. The three of them set off in Damon's carriage, with the servant walking silently, leading the horses.

To get out of the harbour area they had to pay a toll, in Roman coin, to a fat, hairy Saxon. Isolde wondered who the toll was being paid to, and the young monk explained that the governments of the four provinces of Britain still functioned, and still collected taxes-though nothing on the scale of 'the old days', as he called them, before the British Revolution and the expulsion of the diocesan tax collectors, a revolt that had occurred when he, Damon, had been about fifteen.

Beyond the harbour, it wasn't an easy journey. The road they travelled was one of the first Roman roads ever built in Britain, her father proclaimed. That might be so, but that must make it very old, and it was so tatty! You could see where cobbles had been prised out, the holes never filled in, and so the road was full of potholes that shook Isolde painfully. Once the servant had to calm the shying horses. He said curtly that there was a body lying in the clogged drainage ditch; flies rising from the decaying corpse had spooked the animals. Isolde looked away and tried to breathe shallowly.

The country itself was quiet. It was a landscape of farms, of stone-walled fields and small wooden buildings. There were even some grand farmhouses, tile-roofed, enclosed by bristling walls. But many of these were evidently empty, shut up or even burned out, and many of the fields were clearly abandoned, their rain-eroded furrows strangled by weeds. It was rare that Isolde saw anybody working the land.

Nennius remarked on this to Damon.

'It's the Saxons,' said the young monk. 'Too many of them around here. So people are packing up and going off to the towns, or to live with relatives further west or north, or in Gaul. Even the rich have sold up, if they can, and cleared out.' He murmured, 'The Saxons are pagans, you know. They don't mix with us.'

Isolde wondered what tensions were concealed behind those simple phrases.

They came upon Camulodunum in the evening. The city itself sat within massive walls; it looked more like a vast fortress than a town.

And in the rolling fields outside the town and beside the river there were more Saxons-many, many of them, warriors with their horses and wives and children, camped out in tents or in clusters of small wooden huts, some of them set up in the bowl of a disused circus. The travellers picked their way uneasily through this loose camp, along the old Roman road. It was almost as if the Saxons were besieging the city. Damon reassured them there was nothing to fear; the Saxons were mercenaries and had been hired by the townsfolk for their protection. Isolde had no doubt that these fierce-looking warriors would be useful to have on your side. But she wondered what might happen if the money to pay them ever ran out.

They entered the city through the west gate. It was a big double archway that had been almost blocked up by chunks of stone, so that only one person could pass at a time. A soldier in very worn armour stood here collecting more tolls, this time on behalf of the curia, the town council.

Isolde was glad to enter the town, just to get away from the desolate and depopulated British landscape. But this was not Rome. The town within its walls was a bowl of rubble, a shattered townscape of derelict houses, weed-choked gardens and silted-up ditches. The baths were shut down, the theatre was a rubble-filled rubbish tip, and even the main road was ankle-deep in filth. There were none of the public buildings she would have expected in a town this size, or if they existed they were being used for something else. There were some grand houses here, but many of them were abandoned, and as they walked by Isolde saw cooking-fires set up on tessellated floors.

Damon said that in the darkest days of barbarian incursions and banditry, the army had moved its weapons workshops and depots and stock pens within the protection of the town walls. So the town had become a fortress once more, as it had been centuries ago at the beginning of its life. Now the Roman army had gone away, of course, but Saxons and other mercenaries still used the infrastructure it had left behind.

Amid the roofless shells, heaps of building rubble and lakes of sewage, there were functioning offices, however, where the town council or the provincial government still collected taxes, organised work levies and administered justice. And Camulodunum seemed to be full of churches, small but solidly built of reused stone and tile, rising out of the general rubbish like mushrooms from compost. 'There are more churches than people,' Nennius joked wistfully.