The old fisherman was a toothless, hapless, faithless cove you would not trust too near you with a filleting knife, but whether from fear or simple cunning he co-operated eagerly. The lad agreed to marry the girl and since Silvia would never abandon Ollia here, we decided that the fisherboy had to come back with us to Rome. His relations looked impressed by this result. We accepted it as the best we could achieve.

The news that she was to be made an honest woman by a sly tyke with a seaweed moustache set Ollia off crying again, as well it might. Larius, from whom we had kept the sordid details in view of his artistic nature, was glowering at me frantically.

'Ollia's slipped up with her bit of whale blubber,' I enlightened him. 'She's just realized why her mother always warned her: she'll spend the next fifty years paying for this mistake. When he's not out after the women he'll be lying in bed all day, shouting for his dinner and calling her a dozy slut. Now you will appreciate why women who can afford it are prepared to risk abortionists' drugs-'

Larius got up without a word and went to help Petronius order the wine.

Helena Justina, who had been talking to the children while Silvia was calming Ollia, shot me the long, cool glance of a senator's daughter who had glimpsed life on the seamy side and decided this too was something any woman who could afford it would spend serious money to avoid.

We managed to make a good night of it, in the desperate way people do when the choice is between dogged survival or sliding under the morass.

As soon as Petronius reappeared with trays of bread and wine flasks the strain began to evaporate. The affectionate touch of his great hands on frazzled heads soothed everyone as he got us organized. Finding myself near Silvia, who did have more troubles than usual that night, I jollied her along with a hand on her knee (the table was so narrow that people sitting opposite were practically on your lap). Silvia kicked Petro, thinking it was him, so without bothering to look up from his mullet he said, 'Falco, keep your hands off my wife.'

'Why do you behave so badly, Falco?' Helena grumbled at me publicly. 'Put your hands on the table and if you must be offensive, ogle at me.'

I wondered morosely whether Helena was so short with me because she was worried about Pertinax being on the run. I watched her, but she knew I was doing it; her pale face resolutely gave nothing away.

It was one of those nights when a troupe of country dancers came, which soon cheered us up with something to scoff at. Anywhere in the world you can see these tired performers; the girls with scarlet ribbons and tambourines who turned out on close inspection to be a mite older than they first appeared; the bright-eyed little card with a fiendish grin and savagely hooked nose who frenetically played the pan-pipes; the aloof, balding character tootling a solemn flute of a kind unknown to musicologists. Shepherds down from the hills, or the inn-keeper's relations, who knows? It was a summer job-a little money, a few drinks, some thin applause, whistles from the locals, and for us the educational extra of slipping out to the latrine and finding one of the dancers leaning on a wall eating a stick of salami-looking less colourful, less cheerful, and decidedly less clean.

These were as good, or as bad, as they ever are. They whirled and glided and kicked their booted heels with just a touch too much disinterest (considering they expected us to put money in the hat), though the girls did smile steadily as they touted round baskets of roses afterwards, cursing under their breath at the big, black-haired young man who was supposed to wring the cash from us. He showed a particular yen to sit down for a drink out of someone else's flagon and take the weight off his quaint dancing pumps. While he was talking to Petronius, I put my arm round Helena and reminisced how in the old days it always turned out that my elder brother Festus knew the flute player, so the children in our party would be given a free instrument from the sad musician's bundle of home-whittled sticks, instead of us having to pay for them…

Petro leaned over to Helena. 'Once he sounds off about his brother, whip his wine cup away!' She did. I let her, because while she was doing it she smiled at me so fondly I felt weak. Petronius chivalrously handed her a walnut. It was one of his accomplishments that he could crack a walnut shell so skilfully he brought out the kernal intact: both halves, still held together cunningly by their papery flange. After she ate it she let her head loll on my shoulder, and held my hand.

So we all sat under a vine trellis into the evening, with the glint of the dark sea beyond a stone abutment, while men in skimpy tunics thumped up the dust in a fine haze over the hibiscus leaves. Ollia had a stomachache and my poor Larius had heartache. I was thinking about my search for Atius Pertinax tomorrow. Helena was smiling dreamily. Petronius and Silvia decided that their holiday had done them as much good as it ever would, and it was time to go home.

None of the new flutes would play. (They never do, but Petro and I would never learn.)

We all walked slowly back to the inn, and because it was Silvana's birthday we made a ceremony of putting the children to bed. I did not know what I would have to go through before I saw Helena again, so I had drawn her to one side for a private farewell. Someone called upstairs that I had a visitor. Petronius winked at me and went down to deal with it.

One of the children, who had reached the state of being as naughty as they dared, scampered after him in her undershift. Twenty seconds later, even over the hubbub upstairs, we heard her screams.

I was first down the corridor and first down the stairs. Petronilla stood rooted in the doorway, still screaming. I picked her up. There was nothing else to do.

Petronius Longus lay sprawled face down in the inn courtyard with both arms outstretched. A savage blow had felled him, struck at the most dangerous, tender area of his neck. The blood which oozed so slowly from the wound said everything.

For one long moment I held his child, and simply stood, unable to move. There was nothing I could do for him. I knew he was dead.

Among the pounding feet that followed me down, Silvia's sandals whispered, then she shot past me like a breath and onto him before I could snatch her back. I thought she gasped, 'Oh, my baby!' but that must have been a mistake.

I pushed the child into someone's arms then ran out and tried to persuade Silvia to leave him. Helena Justina squeezed in alongside me and knelt by his head so she could gently check for a breath or a pulse.

'Marcus, come and help me-he's alive!'

After that she and I worked as partners. Life held some hope again. There were things to do.

Larius tore off on a donkey in search of a doctor. Ollia, with surprising sense, extricated Silvia. I did not want to move Petro, but it was growing darker every minute and we could not leave him out there. Helena commandeered a room on the ground floor-paid for it, I think-then we carried him in on a hurdle.

He should have been dead. A smaller man would have been. I would be. Presumably some villain who specialized in pointless gestures now thought I was.

He was deeply unconscious, so deeply it was dangerous. Even if he ever woke, he might not be himself. But he was a big, fit man with the physical strength to match; there was stamina and determination in everything he did. Larius found a doctor who salved the wound, reassured us that Petronius had not lost much blood, and said all we could now do was keep him warm and wait.