At Moguntiacum there was just one, responsible for the whole fort. Since the Fourteenth were the only experienced legion stationed there, he had been supplied by them.

The camp prefect occupied an office whose oversized proportions must have appealed to his underdeveloped personality. I found him in it. He was reading scrolls and writing busily. He had made his nook deliberately spare. He used a folding stool with a rusted iron frame and a campaign table that looked as if it had served at Actium. It was supposed to give the impression that he would have preferred to be on active duty in the field. In my view, if Rome was to sustain any military reputation, men like this had to be kept in camp-gagged, bound and bolted to the floor.

'Sextus Juvenalis? I'm Didius Falco. The envoy from Vespasian.'

'Oh I heard some worm had poked its head out of a hole on the Palatine!' He wrote with a quill. He would.

Setting down the quill, meticulously balanced on the ink-pot in a way that prevented drips, he bounced at me: 'What's your background?'

I assumed he didn't want to hear about my aunties in the Campagna. 'National service in the usual stinking province, then five years as a scout.'

'Still in uniform?' Army life was his only social yardstick. I could imagine him boring everyone rigid with his stubborn theories that traditional values, antique equipment and dreadful old commanders whose names no one had heard of were unsurpassed by their modern equivalents.

'Self-employed now.'

'I don't approve of men who leave the legions before time.'

'I never supposed you would.'

'National service lost its glint?'

'I copped a tricky spearhead wound.' Not as tricky as all that, but it got me out.

'Out of where?' he persisted. He should have been an informer.

'Out of Britain,' I admitted.

'Oh we know Britain!' He was eyeing me narrowly.

I braced myself. There was no escape. If I dodged any more he would guess anyway. 'You know the Second Augusta then.'

Sextus Juvenalis barely moved, but contempt seemed to flood his features like new colour in a chameleon. 'Well! You were unlucky!' he sneered.

'The whole Second were unlucky-in a certain camp prefect called Poenius Postumus!' Poenius Postumus was the imbecile who had ignored orders to join battle against the Iceni. Even we never really knew what his motives were. 'He betrayed the Second just as much as the rest of you.'

'I heard he paid for it.' Juvenalis lowered his voice a semitone, overcome by horrified curiosity. 'The word was, Postumus fell on his sword afterwards. Did he fall -or was he dropped?'

'What do you think?'

'Do you know?'

'I know.' I was present. We all were. But what happened on that angry night is the Second Augusta's secret.

Juvenalis stared at me as if I were a guardian at the gates of Hades with a downturned torch. He rallied soon enough, however. 'If you were with the Second, you'll need to tread carefully here. Especially,' he added heavily, 'if you are Vespasian's private agent!' I put up no attempt to quibble. 'Or is it your fancy companion?'

'So people have noticed Xanthus?' I smiled quietly. 'I honestly don't know his role. I prefer not to.'

'Where did you acquire him?'

'An unsolicited gift from Titus Caesar.'

'Reward for past services?' the prefect sneered.

'I suppose it could be for future ones.' I was ready to tighten the ligature: 'You're the best man to make excuses for the Fourteenth. Let's talk about Gracilis.'

'What's to say?' Juvenalis queried in a light tone. He appeared to be taking the reasonable line. I was not fooled.

'I need to see him.'

'It can be arranged.'

'When?'

'Soon.'

'Now?'

'Not immediately.'

I shifted restlessly. 'October in Upper Germany is hardly the time or place for legates to be snatching unofficial holidays.'

'He doesn't ask advice from me.'

'Perhaps he should!' Blatant flattery was also a failure. Camp prefect is an immodest rank; he thought it was his due. 'Maybe taking advice is not your legate's strong point. I hear he's been making himself unpopular.'

'Gracilis has his methods.' He defended his commander loyally. Nevertheless, I saw the flicker behind the prefect's eyes-annoyance at the legate's abrasive attitude.

'So is he off with a woman, or moonlighting from the bailiffs?'

'Official business.'

'Tell me. I'm official too.'

'It's officially secret,' he jeered. He knew I had no comeback. Men like that can judge your status from the way you lace your boot-thongs. Mine must have been twisted the wrong way.

'I have my orders, Prefect. If I can't carry them out, I may have to send a query back to Rome.'

Juvenalis let a thin smile play on his lips. 'Your messenger won't leave the fort.' I was wondering how much I could remember of the smoke-and-bonfire semaphore code when he forestalled me contemptuously: 'You'll find the signal station out of bounds.'

'And I don't suppose Moguntiacum keeps carrier pigeons?' I gave way with an air of grace I didn't feel. But I preferred not to find myself in the tiny cells beside the main gate, rationed to one bowl of barley gruel a day. I changed tack. 'I was sent here to take political soundings. If I can't get a briefing from Gracilis, I'll have to pick your brains instead. What's the mood among the local tribes?'

'The Treveri were roundly beaten by Petilius Cerialis.' Juvenalis ground it out in a tone which implied he was too long in the tooth to be openly obstructive, though he could easily spoil my mission if he decided to.

'At Rigodulum? The Twenty-first Rapax did well for Cerialis there!' I replied, jibing at the Fourteenth's less notable contribution.

Juvenalis ignored it. 'The tribes have gone back to earning their living and keeping their nasty heads down.' This was unexpectedly helpful. No doubt he was hoping I would go out into the local community and offend someone there, to save him the trouble of smacking me senseless.

'What are the staple industries hereabouts?'

'Wool, shipping on the river-and ceramics,' Juvenalis informed me, striking a chord with that last one.

'Cloaks, boats and pots! Didn't the rebel leader Civilis have family contacts in this area?' I asked. 'I'm told his wife and sister stayed at Colonia Agrippinensium during the revolt.'

His face set. 'The Batavians come from the north coast.'

'Spare me the geography lesson, Prefect. I know their habitat. But Civilis has made himself scarce from The Island and that whole region. I have to find him-I wonder if he's been back south?'

'Funnily enough,' Juvenalis replied, with some sarcasm, 'we do hear of him being sighted from time to time.'

'Really?'

'It's just rumour. He had a certain mystique among his people. When men like that die or disappear, you'll always find fake versions.'

He was right, up to a point. In the early days of the Empire, impersonators of tyrants were a constant phenomenon: Caligula, for instance, was continually being reborn among crazy supporters in exotic eastern states.

'So you reckon these rumours of local sightings are all moonshine?'

'He's a fool if he comes anywhere near the Fourteenth!' The defection of their Batavian cohorts obviously rankled sorely.

'Do you send out patrols to investigate?'

'They find nothing.'

I thought that did not necessarily mean there was nothing to find. 'What are the chances rebellion will flare again among the tribes?' Juvenalis did not regard it as a function of his appointment to give political briefings, so I let myself speculate: 'It's the old joke still. If a Greek, a Roman and a Celt are shipwrecked on a desert island, the Greek will start a philosophy school, the Roman will nail up a rota-and the Celt will start a fight.' He glared at me suspiciously; even as a joke it was too metaphysical. 'Well, thanks-' I never finished, for the door opened.