Friends of the favoured Rutilius began to arrive. I had heard their loud, high-class voices chaffing him before they ambled down here. They poured in and strolled past, ignoring me, then headed automatically for the best seats. Amongst a group of female freedwomen, came a dumpy woman whom I identified as his wife, stiffly coiffed with a crimped tower of hair and well dressed for the occasion. She seemed to be wondering if she ought to speak to me, then she decided to introduce herself to Helena. 'I am Minicia Paetina; how very nice to see you here, my dear…' She eyed the respectability curtain and was roundly advised by Helena to reject it. Minicia looked shocked. 'Oh, I may feel more comfortable out of the public gaze…'

I grinned. 'Does that mean you have heard your husband read before, and don't want people seeing what you think?'

The wife of Rutilius Gallicus gave me a look that curdled my stomach juices. These northern types always seem rather cold to those of us who are Roman-born.

Do I sound like a snob? Olympus, I do apologise.

My own friends came late, but at least this time they did come. My mother was first, a beetling, suspicious figure whose first action was to stare hard at the marble floor, which in her view could have been better swept, before she showed her affection for me, her only surviving son: 'I do hope you are not making a fool of yourself, Marcus!'

'Thanks for the confidence, Ma.'

She was accompanied by her lodger: Anacrites, my ex-partner and arch-enemy. Discreetly smart, he had treated himself to one of the snappy haircuts he favoured and now flourished a knuckle-crushing gold ring to show he had reached the middle class (my own new ring, bought for me by Helena, was merely neat).

`How's the snooping trade?' I sneered, knowing he preferred to pretend nobody knew he was the Palace's Chief Spy. He ignored the jibe, leading Ma to a prime seat in the midst of Rutilius' snootiest supporters. There she sat bolt upright in her best black gown, like a grim priestess allowing herself to mingle with the populace yet trying not to let them contaminate her aura. Anacrites himself failed to find space on the marble perch, so curled up at Ma's feet, looking as if he was something unsavoury she had caught on her sandal and could not shake off.

`I see your mother's brought her pet snake!' My best friend Petronius Longus had failed to wangle himself a night's leave from his duties as enquiry chief of the Fourth Cohort of Vigiles, but that had not stopped him bunking off. He arrived in his working clothes – sturdy brown tunic, brutal boots and a night-stick – as if he was investigating a rumour of trouble. That lowered the tone nicely.

`Petro, we're planning to read love poems tonight, not plot a republican coup.'

`You and your consular pal are on a secret list as potential rioters.' He grinned. Knowing him, it might even be true. Anacrites had probably supplied the list.

If the Second Cohort, who ran this sector of town, discovered him moonlighting on their ground, they would thump him. It did not worry Petro. He was capable of thumping them back good and hard.

`You need an invigilator on the doors,' he commented. He stationed himself on the threshold, unwinding his stick in a meaningful manner, as a flock of strangers crowded in. I had already noticed them, due to their curious mixture of unattractive haircuts and misshapen footwear. There were some effete vocal accents, and a whiff of bad breath. I had invited none of these odd chancers, and they did not look as though they would appeal to Rutilius Gallicus. In fact, he came scuttling after them with an annoyed expression, helpless to intervene as they gatecrashed.

Petronius blocked the way. He explained this was a private party, adding that if we had wanted the general public, we would have sold tickets. At the crude mention of money, Rutilius looked even more embarrassed; he whispered to me that he thought these men belonged to a circle of writers, who were attached to some modern patron of the arts.

`Thrills! Have they come to hear how good writing should be done, sir – or to heckle us?'

`If you're looking for free wine, you're in the wrong place,'

Petronius warned them loudly. Intellectuals were just another cudgel-target to him. He had a bleak view of literary hangers-on. He believed they were all on the cadge like most of the crooks he dealt with. True.

The man who doled out their pocket money must be approaching, because the group started paying attention to a flurry further up the ramp. The patron they grovelled to must be the pushy type with the Greek beard who was trying to impose himself on a paunchy, disinterested young man of twenty-something, a new arrival whom I certainly did recognise.

`Domitian Caesar!' gasped Rutilius, absolutely thrilled.

HELENA KICKED me as I cursed. This was not simply because I wrote sensitive poetry that I regarded as private chamber stuff, nor because of my libellous satires. True, I did not welcome a blaze of imperial notice tonight. I would have to censor my scroll.

Domitian and I had a bad relationship. I could damn him, and he knew it. This is not a safe position with holders of supreme power.

A few years before, in the chaotic period when we were repeatedly changing emperors, many things had happened that later seemed beyond belief; after a brutal civil war, plots of the worst kind were rife. At twenty, Domitian had been badly supervised and he lacked judgement. That was putting it kindly – as his father and brother had chosen to do, even when he was rumoured to be plotting against them. His bad luck was that in the end, I was the agent called in to investigate. It was my bad luck too, of course.

I judged him on the facts alone. Fortunately for Titus Flavius Domitianus, second son of Vespasian, as a mere informer I did not count. But we both knew what I thought. During his machinations, he was responsible for the murder of a young girl towards whom I had once felt some tenderness. `Responsible' is a diplomatic euphemism there.

Domitian knew that I held damning information, reinforced by well-stashed evidence. He had done his best to keep me down – so far only daring to delay my social promotion, though the threat of worse would always exist. So too, would a threat against him from me, of course. We both knew there was unfinished business between us.

This now promised to be a difficult evening. The uppity young Caesar had been demoted to running literary prizes. He seemed to judge them impartially – but it was unlikely that Domitian would be a friendly critic of my work.

Brushing off everyone else except Rutilius, the princeling swaggered by, in company with his glamorously tricked out wife, Domitia Lepida – the great general Corbulo's daughter, a spectacular prize whom Domitian had blatantly carried off from her former husband. He ignored me. I was getting used to that tonight.

In the excitement, the gatecrashers managed to gain entry, but it now seemed best to allow in the largest audience we could commandeer. Among the final comers I suddenly saw Maia; she made a typically swift arrival, her dark curls and self-possessed air turning heads. Petronius Longus made a move to escort her to a seat, but she squeezed through the press, bypassed both Petro and me, boldly made her way to the best position in the room, and forced herself a niche alongside Ma. The imperial party should have been ensconced in state there at the apsidal end, but they remained to one side. Courtiers hoicked themselves up onto shoulder-high wall ledges. Domitian deigned to sit on a portable bench. I recognised – as Rutilius may not have done – that this was a courtesy visit only; the royal troupe had dropped in to be gracious, but were leaving themselves space to make a getaway as soon as they grew bored.