I saw Lentullus creep back after his pee in the woods. He looked furtive, which was nothing unusual. He also looked frightened.

He said nothing to anyone. I decided to ignore it, then found that was impossible. I strolled across to him.

'All right?'

'Yes, sir.'

'Anything to tell me?'

'No, sir.'

'That's a relief.'

'Well, sir: ' Oh dear! 'I think I saw something.'

Lentullus was the type who would spend three days wondering whether he ought to mention that a large army of warriors in wicker chariots with war horns and broadswords was heading our way. He never knew what was important. Lentullus would get us killed rather than say anything to worry the command.

'Something alive?' I asked him.

'No, sir.'

'Someone dead?'

Lentullus paused and would not answer me. All the hairs on my neck and arms rose slowly to attention.

'Come along, Lentullus. Let's you and I take the tribune's puppy for a walk.'

We hacked through the woods for about ten minutes. Lentullus was a shy soul. We had lost him twice already when attending to nature had led him so far from the camp that he couldn't find us afterwards. He stopped to take bearings. I kept quiet rather than confuse him completely. The thought struck me that we could be out here all night while Lentullus searched for his treasure again.

I hate forests. With everywhere completely motionless, it would be easy to become terrified. Among these trees bear, wolves, elk and boar all roamed. The chill air smelt damp, with an evil autumnal unhealthiness. The vegetation was a rank, flowerless kind, with no known herbal use. Fungi like lined faces hung in ancient trees. Undergrowth caught at our clothing and flesh, snagging our tunics and scratching our arms vindictively. My breastplate had become splattered with some sort of insect juice. At this spot we seemed to be the only things breathing apart from eerie watchers from the Celtic spirit world. We could sense a lot of them, both remote and close by.

Twigs snapped, too near for comfort, the way forest twigs do. Even Tigris was subdued. He stayed close to us instead of rushing off to scavenge for woodvoles and bad smells.

'I don't like it here, sir.'

'Show me what you found, then we can go.'

He led me through a few more thickets, over a giant log, past a dead fox which had been torn at by something much larger-something that was probably planning to come back for the rest of it just about now. Tigris growled worryingly. A cloud of midges was mobbing my forehead. 'This is where I was standing. I thought that it looked like a path.' Maybe. Or just a coincidental space among the crowded trees. 'I went along it for a look:' He was congenitally curious. And daft. Lentullus would pick up a scorpion to see if it's true they sting.

I still had no idea what he had seen, except that its effect on the recruit chilled me. 'Come on then.'

We took the supposed path. Maybe deer came this way. The air smelt even more hostile, and the light was fading fast. Dew had made our boot-leather swell, and our feet dragged with clumsiness. Leaves crunched under foot louder than I liked. Our progress must have been audible for a couple of miles.

Then the trees stopped.

I was tired. I was cold and uneasy. At first my eyes refused to focus, fighting disbelief. Then I understood why the recruit had been afraid of his discovery.

The silent clearing we had entered lay hung with mist. It was a big clearing, or had been once. Ahead of us lay a strange low sea of brambles. The brambles and brushwood sank slightly nearer to us, then rose many feet away to a regular berm of woodland. The moatlike depression stretched sideways in each direction. The canes dipped, as if the ground beneath their tangled mass had been cut away. And so it had. We knew that, even without venturing forwards-which would have been deadly dangerous. Almost at our feet the ground must fall steeply, deeper than a man's height. Below us, invisible in the brambles, fiendishly sharpened stakes no doubt snarled. At the bottom of the ditch would be a trim channel one spade wide for drainage, then the farther wall would rise diagonally into a bank, before falling back to level ground. There, woodland filled the berm. Comparatively young woodland, not the ancient trees we had been struggling through all day, which must have been standing sturdily in the old times of legend when Hercules visited Germany.

It was a different legend we had found.

Beyond the wood there was a rampart. We could glimpse only the upper part above the vegetation. But there had to be a patrol track, faced with a timber palisade and broken by the shape of familiar square towers. Further on in the gloaming we made out the formidable bulk of a standard fortress gate.

It was silent. No sentries were patrolling and no lights showed. But here, a hundred miles from the Roman provinces, stood a Roman camp.

XLV

'Sir, is anybody there?'

'Dear gods, I hope not!' I was in no mood for exchanging travellers' tales with dead men or their ghosts.

I started to move.

'Are we going in?'

'No. We're going back.' I turned him round.

'Sir, we could camp inside-'

'We'll camp where we are:'

Few of us slept much that night. We lay awake, listening for trumpet calls from Hades, then nodded off just before dawn. I woke early and rose while it was still dark, stiff and snuffle-headed. The rest emerged too. After a cold drink and some biscuit to brace us, we packed, brought the horses, and then set off in a close group to make a morning call on our colleagues' camp. At dawn, it managed to look even lonelier.

This was no Vetera. It was a field army's camp, and a large one. Though intended as a temporary construction, it stood in its isolation with an air of permanence. There were no signs of siege warfare. Decay, however, clung tenaciously. Apart from the rich clothing of brushwood on the outworks, some of the towers had lurched and the palisades collapsed. We could see now that further along from us the actual breastwork was broken down.

We battered a path to the gatehouse. One of the great wooden doors lay off its hinges. We edged just inside, no more. A spider the size of a duck's egg watched us entering.

The vegetation was dramatic. Everything within the ramparts was wrecked.

'Sir, was there a fight?'

'No bodies left, if there was.' Helvetius, alone of us, dismounted and wandered forwards to explore. Even he had no intention of going far. He stopped and picked up a small object. 'I don't think the place was abandoned,' he murmured in a puzzled voice.

He began to make his passage further in, and this time we followed him. It would have been a tented camp, so there were large tracts of open ground where the long leather 'butterflies' would have been pitched in rows. But wherever the legions stay for any length of time, the storehouses and the Principia are made from permanent materials. These should have been evident, in their familiar locations, as squares where only a low covering of thin weeds grew, because of their solid floors, yet rotting old timbers and mounds of other wreckage occupied their sites.

'What's your verdict, centurion?' Justinus asked. He was white-faced from the early hour, lack of sleep and anxiety.

'It was an empty camp-but not dismantled normally.'

'They had left for the winter,' I said. I spoke with some confidence. The shrine and strongroom, built of stone, still stood erect. There were of course no standards and no eagles in the shrine. I had seen the gold eagles that once flew here. I had seen them in the Temple of Mars in Rome.

Helvetius looked at me. He too knew what we had found. 'That's right. The buildings were all left here. Bad practice, but they expected to come back, of course.'