'Very wise.'

We had a flagon. 'The wine's rather basic here:' Justinus was either too timid or too lazy to be rude to his wine merchant. It tasted like goat's pee (from a goat with bladder stones), but a glass in the hand helped pass the time. 'So Marcus Didius, why did you come through my old base?'

He must have known I was looking for Helena. 'Looking for you.'

'Oh that was kind!' He managed to sound as if he meant it.

'I thought you might like news of your family. They all seem well. Your father wants to buy a yacht but your mother won't hear of it: Have you heard from your sister recently?'

I posed the question before I could stop myself; too late to make my interest sound merely banal. Justinus whipped back, 'No, she seems unusually quiet these days! Is there something I ought to know?'

He must have heard about her choosing to eat the gritty bread at my table. Explaining our relationship was beyond me. I said briefly, 'She's taken herself off from Rome.'

'When?'

'Just before I came away.'

Justinus, who was reclining on an army-issue reading-couch, stretched slightly to ease the pressure on his arm. 'That seems rather sudden!' He was laughing, though I could see solemnity looming. 'Did someone upset her?'

'Probably me. Helena has high standards and I have low habits: I hoped she might have invited herself to stay with you.'

'No.' The reason for my keen interest still hovered unhealthily, but remained unsaid. We both felt shy of turning that boulder. 'Should people be worried?' Justinus asked.

'She's sensible.' Justinus thought a lot of his sister and was prepared to accept that. I cared about her too, and I was not. 'Tribune, as far as I know your sister made no arrangements with her banker, and took no bodyguard. She never said goodbye to your father; she completely bamboozled your mother; she surprised mine, who is very fond of her; and she left no forwarding address. That,' I said, 'worries me.'

We were both silent.

'What do you suggest, Falco?'

'Nothing. There's nothing we can do.' That worried me as well.

We changed the subject.

'I still don't know,' Justinus broached, 'how you came to be here seeking a missing legate the minute we had a problem with Gracilis?'

'Coincidence. The one I'm chasing is Munius Lupercus.'

'Olympus! That's a forlorn hope!'

I grinned unhappily.

Several of his relatives were close to the Emperor, and I felt satisfied that Justinus had inherited their discretion. I spoke freely about my mission, though I shied off mentioning the XIV Gemina. This courtesy to them was probably pointless, but I do have some standards. 'One or two challenges!' he commented.

'Yes. I've already discovered that the prophetess Veleda lives at the top of a tower, and can only be approached through her male friends. This must be to endow her with a sinister aura. Going across the Rhenus river unnerves me enough, without any theatricals!' Justinus laughed. He could. He didn't have to go. 'You seem the type who keeps up to date, Justinus. Can you tell me anything about the rebel chief?'

'Civilis has disappeared-though there are plenty of stories about his horrible habits!'

'Thrill me!' I growled.

'Oh, the most lurid anecdote has him handing over Roman prisoners to his small son as targets for arrow practice.'

'True?'

'It could be.'

Wonderful. Just the sort I enjoy taking out to a wine bar so I can have a quiet word in his ear. 'Before I try to buy a drink for this civilised parent, is there anything less colourful that I ought to know?'

I knew the general background. Before the revolt the Batavians had always had a special relationship with Rome: their lands were exempt from colonisation-and therefore from taxes-in return for them supplying us with auxiliary troops. It was not a bad bargain. They got excellent pay and conditions-a vast improvement on what they could achieve by the rough-and-ready Celtic tradition of raiding their neighbours when the grain pits ran low. We acquired their nautical skills (pilotage, rowing and swimming). They were famous for being able to cross rivers in full kit, paddling alongside their horses.

Justinus plunged straight in, cogently and without floundering: 'You know Julius Civilis is a member of the Batavian royal family. He spent twenty years in Roman military camps, leading auxiliaries for us. When the recent upsets started, his brother Paulus was executed as a troublemaker by the then governor of Lower Germany, Fonteius Capito. Capito sent Civilis himself in chains to Nero.'

' Were they troublemakers at that stage?'

'The evidence suggests it was a trumped-up charge,' Justinus declared in his measured way. 'Fonteius Capito was a highly dubious governor. You know he was court-martialled and killed by his own officers? He had a reputation for governing greedily, but I can't tell you whether that was justified. Galba omitted to investigate his execution, so perhaps it was.' Or perhaps Galba was a geriatric incompetent. 'Anyway, Galba acquitted Civilis of treachery, but only lasted eight months as emperor, so then Civilis became vulnerable again.'

'How come?' I asked.

'When Vitellius seized power his armies called for various officers to be put to death, ostensibly for loyalty to Galba.' I remembered that nasty episode now. Quite blatantly, it had been about settling old grudges. Unpopular centurions were the main target, but I knew the troops had also clamoured for the Batavian leader's head. Vitellius ignored them and confirmed Galba's 'pardon', but it must all have left Civilis with a great bitterness against his so-called Roman allies. 'Also in that period,' Justinus went on, 'the Batavians were being sorely treated.'

'Example?'

'Well, for instance, during conscription for Vitellius, imperial agents were calling up the infirm and the old in order to extract bribes for their release from the levy. And young lads and lasses were dragged behind the tents for unpleasant purposes.'

Batavian children tend to be tall and good-looking. All Germanic tribes have a strong sense of family, so this treatment must have festered sordidly. That was why the next imperial claimant, Vespasian, had felt he could call on Civilis to help him oppose Vitellius. But far away in Judaea, Vespasian had misread the situation. Civilis co-operated at first, in alliance with a tribe called the Cannenefates. They made a joint attack on the Rhenus fleet, thereby capturing all the arms and ships they needed and cutting Roman supply lines. Vespasian was then proclaimed Emperor.

'That forced Civilis to come out in his true colours,' Justinus explained. 'He summoned all the chiefs of the Gallic and German tribes to a meeting in a sacred grove in the forest, let the wine flow freely, then fired them with powerful speeches about shaking off the Roman yoke and establishing a free Gallic empire.'

'Stirring stuff!'

'Oh, highly dramatic! Civilis himself even dyed his hair and beard bright red, then swore never to cut them until he had driven out every Roman.'

This colourful detail gave my own mission a picturesque quality I hated. 'Just the sort of ethnic madman I love trying to outwit! Did he ever shave?'

'After Vetera.'

We were silent for a moment, thinking of the siege.

'A fort like that should have held out.'

Justinus shook his head. 'I haven't been there, Falco, but by all accounts Vetera was neglected and understaffed.'

We buried ourselves in the tribune's gruesome wine, while I reflected sourly on what I had heard about Vetera.

It had been a double fort, though nowhere up to strength after Vitellius had drawn off large vexillations for his march on Rome. The remnant of the garrison put up the best show they could. Plenty of initiative. But Civilis was Roman-trained in siege warfare. He made his prisoners build battering-rams and catapults. Not that the defending legions lacked invention: they had devised an articulated grab that could scoop up attackers and toss them into the fort. But by the time they surrendered, they really had eaten all the mules and rats and were down to chewing roots and grass torn from the rampart walls. Besides, with the civil war raging in Italy, they must have felt completely cut off. Vetera was one of the most northerly forts in Europe, and Rome had other preoccupations.