I myself was temporarily in trouble. While Musa and I were hanging on to each other getting our breath back, a familiar voice stormed angrily: 'Didius Falco, if you really want to kill yourself, why not just get run over by a dung-cart like everybody else? Why do you have to attempt your destruction in front of two thousand strangers? And why do I have to be made to watch?'

Magic. I was never so happy as when Helena was berating me. It took my mind off everything else.

'May as well sell tickets for the fight, and help you pay for my funeral -'

She growled, dragging the ghost's costume up and over my head to give me air. But it was a gentle hand that wiped my perspiring brow with her own white stole.

Then we were rushed by the Habib family. They had burst from their seats to tell us what a wonderful evening we had invited them to share – and to stare hard at Helena's lanky chaperone. I left the next part to the women. Helena and Thalia must have planned it in advance, and while Helena was taking her up into the tribunal, Sophrona must have been instructed to go along with it.

Helena hugged the girl, then cried to the Habib family gratefully, 'Oh thank you for looking after her – I've been searching all over for the naughty thing! But now she's found and I can take her back to Rome with me to her proper life. I expect you realised she was from a good family. Such a talented musician, but wicked to run away to be on the stage, of course. Still, what can you expect. She plays the instrument of emperors:'

I was choking quietly.

The Habib parents had weighed up the quality of Helena's jewels, some of which she must have been buying quietly from Nabataean caravans and Decapolis markets while my back was turned. They had seen the commanding officer treating her with extreme respect, since he knew that Vespasian himself wanted her whereabouts reported on. Now Khaleed put on a beseeching look. His father was salivating over their apparent good luck. Sophrona herself, like most girls, found she could easily slip into the appearance of being better than she was.

Khaleed's mother suggested that if the girl had to leave Syria, maybe the young couple could be married first. Helena then proposed that Khaleed should spend some time in Rome improving himself among the nobility:

'Isn't that nice?' uttered Thalia, with no apparent trace of irony. Nobody but me seemed to entertain any notion that once in Rome the forceful Thalia would persuade Sophrona that her best interests lay not in settling down, but in her public career as an organist.

Discussion was avoided because of a rumpus in the amphitheatre. Denied a full programme, the angry soldiers had started to tear up benches from the ramps.

'Jupiter! Better stop this! How can we distract them?'

'Easy.' Thalia grabbed hold of the young lady. 'Now you're nicely sorted out, Sophrona, you can do something in return. Buck up! I didn't bring it all the way from Rome just to let mosquitoes breed in the water tank:'

She signalled to her staff. With a speed that astonished us they lined up around a large low carriage. Calling some of Chremes' stagehands to help them, they wheeled it to the gate, counted three, then ran out across the open space. The audience stilled, and quickly resumed what was left of their seats. The shrouds dropped from the looming item. It was a hydraulus.

When levered off its carriage, the water organ stood over twelve feet high. The upper portion looked like a gigantic set of syrinx pipes, made partly of bronze, partly of reed. The lower part was formed from an ornamental chest to which bellows were attached. One of Thalia's men was pouring water carefully into a chamber. Another was attaching a footboard, a huge lever, and a keyboard.

I saw Sophrona's eyes widen. For a few moments she managed to hide her eagerness, performing a brief pageant of reluctant maidenhood. Helena and the rest of us went along with it and pleaded with her to take the stage. Next minute she was bounding out to give orders to those setting up the instrument for her.

It was obvious that playing the organ mattered. I decided I ought to introduce Sophrona to Ribes. Our moody lyre-player seemed like a young man who might be done a power of good by a girl with wonderful eyes who could talk to him about music:

Thalia grinned at Davos. 'Going to help me pump her bellows?' She could make the simplest question sound cheeky. Davos accepted the dubious invitation like a man, even though Thalia had a glint that promised even harder work for him afterwards.

A decent fellow. I reckoned he would cope. Just as they were about to leave us to provide Sophrona's support on-stage, Phrygia called Thalia back. She had teetered up, her long gangly figure balancing precariously on platform heels. She was waving at the equally tall figure of Sophrona.

'That girl:' She sounded anguished.

'Sophrona? She's just a waif I inherited with Fronto's circus.' The narrowing of Thalia's eyes looked unreliable to anyone who wasn't desperate.

'I hoped my daughter was here:' Phrygia was not giving up.

'She's here. But maybe after twenty years alone she doesn't want to be found.'

'I'll make everything up to her! I can offer her the best.' Phrygia gazed around wildly. Only one other female in our circle was the right age: Byrria. She snatched at the younger actress hysterically. 'We took you on in Italy! Where were you brought up?'

'Latium.' Byrria looked calm, but curious.

'Outside Rome? Do you know your parents.'

'I was an orphan.'

'Do you know Thalia?'

I saw Thalia wink at Byrria. 'Obviously,' said Thalia quietly, 'I never told your daughter a famous actress was her mother. You don't want girls getting big ideas.'

Phrygia threw her arms around Byrria and burst into tears.

Thalia shot me a look, one of calculation and amazement at what fools would believe when their eyes should tell them different. Then she managed to grab Davos and escape into the arena.

'Everything is going to be wonderful from now on!' Phrygia cried to Byrria. Byrria gave her the doubtful grimace of the usual ungrateful daughter who wants to make her own life.

Helena and I exchanged a glance. We could see the young actress considering what to do as she recognised her amazing luck. Out in the arena, Sophrona had no idea she was being displaced; she was being given plenty of options anyway. Byrria's determination to gain a place in the world had never been in doubt. She wanted a career. If she played along with Phrygia's mistake, she could not only demand good acting parts, but without a doubt she would sooner or later end up in command of the whole company. I reckoned she would be good at that. Loners can usually organise.

What Chremes had told us about the death of live theatre would probably not count. He had been despondent. There was still scope for entertainers, certainly in the provinces, and even in Italy if they adapted to the market. Byrria must know she had been offered the chance of her life.

Chremes, who appeared to need more time than his wife to consider his position, gave Byrria an embarrassed smile, then led Phrygia away to join most of our company, who had collected inside the gate of the amphitheatre. They were eagerly waiting to judge Sophrona's keyboard skills on the fabulous instrument. Byrria dallied behind with Musa, Helena and me. On the whole, I thought Chremes' position was a good one. If he kept his head down he could keep his wife, find himself promoting a popular and beautiful young actress, and probably have peace at home.

Davos, I thought, might soon want to be leaving the company.

If Davos joined forces with Thalia, there seemed a possibility that Sophrona might have lost a mother, but gained a father here today.

I lurched to my feet. 'I'm not a great fan of sonorous music' Especially after a nerve-racking physical experience. 'Don't let me spoil the fun for anyone else, but if none of you mind, I've had enough of this.' They all decided to come with me back to camp.