Eventually, Negrinus emerged and hopped agitatedly on the doorstep until transport was brought for him. I tailed him and was not surprised by where the smart litter headed. He went straight to his mother, like a devoted boy.

Wrong. He went to her house. But her outcast son did not want to see his cruel mama.

In the street outside the Metellus mansion with its yellow Numidian obelisks, he shed the litter and secured an observation post. He got the bar counter – which left me, when I arrived, hiding behind a stinking row of fish-pickle amphorae. He bought a beaker of hot, spiced wine; I had left my drink behind at the previous place. Typical. He was the suspicious character; I was the upright informer. The Fates would adorn him with comforts; I was stuck with a rumbling stomach and a cold arse.

What was he doing? When I realised, a sneaky fellow-feeling arose. The noble Metellus Negrinus was waiting for his mother to go out.

Calpurnia left home in her litter, which was a beaten-up chaise carried by two elderly bearers, one who seemed to have gout, neither. in uniform. I could see she was the passenger, because the curtains were missing. A miserable female slave, shivering in a thin gown, wandered behind on foot.

She still had possession of the family home, but it looked as if Calpurnia Cara was already down on her luck. Had Paccius Africanus stepped in already and laid claim to domestic goods and slaves?

Was Paccius then absolutely sure the three children would not, or could not, contest their father's odd will?

Negrinus must have known his mama had an appointment. Once her straggling party turned the far corner of the street, he quickly paid for his wine (was the supportive Carina giving him dole money?) then he marched straight across the street. He was using his latch-lifter when the door opened anyway. After a brief conversation, someone let him in. I allowed time for him to start whatever he was planning, then approached the fine front door myself.

I knocked nonchalantly. A slave I failed to recognise appeared after a long pause. `About time.' I glared with my good eye. `Wow! What happened to you?'

`I looked up and a passing eagle shat very hard in my peeper… So where's Perseus?'

`Having his lunch.'

`He has a nice life.'

`You bet!' It was said with feeling.

`I suppose he'll enjoy several courses and a snug flirtation with the kitchen maid, then stretch out for a relaxed siesta?'

`Don't ask me!' This lad buttoned up. He knew better than to gossip any further, but he had let me see he was unhappy. So, in Perseus we had that stock character: the uppity slave who abuses his position – and who somehow gets away with it.

I tipped the substitute. He let me in. `He's a character!' I chortled. `Somebody's favourite is he, your Perseus?' Not from the way I had heard Calpurnia address the lackadaisical beggar before. His neglect of his duties had made her rightly furious. But if something had gone on between Metellus senior and Saffia, and if Perseus knew about it, his arrogance would make sense.

We had a recognisable situation – though rare in a porter. More often, the uppity slave has intimate contact with the master or mistress of the house. In a boudoir maid or a correspondence clerk, abuse of status arises much more easily.

'Perseus has influence,' was all I could extract. Maybe my tip was not large enough. Or maybe the staff had learned that it was best to keep quiet.

My next contact was with the superior steward whom I had met on my first visit here. Instinct warned him of trouble and he arrived in the atrium, napkin under his chin. He glanced at my bandage but was too well trained to comment. Losing the bib suavely, plus the smear of oil on his chin from his abandoned lunch, he accompanied me on the track of Birdy. We found him in what must have been his bedroom once. He said he had come to collect clothing – fair enough, and a few desultory choices of tunics were made as he rummaged. He was looking for something else, though.

`My wife is in labour. I had a message that the baby is taking a long time. She is restless, and her women think she might be more comfortable with her own bedding…'

`I was told Saffia's stuff was "stolen" when she left here,' I said.

`If chattels went astray,' the steward put in indignantly, `I knew nothing of it.'

`You should,' snapped Birdy. `Saffia has been erupting.'

The steward believed the missing items could be found. He went off to investigate. Negrinus continued throwing his own possessions together for removal to his sister's house. Goading him, I commented, `I was told that your communication with Saffia had broken down.'

'Ah, but now Saffia wants something!' Negrinus spoke with a new bitterness. He stood in the centre of his old bedroom. It was a finely decorated room in bluey-green, with curliculed pictures of sea monsters. His feet were planted on a well modulated geometric mosaic. All this decor went back several decades and was starting to look tired. So was Birdy. He ran his hands through his hair. He had looked neat when I first met him, but he now needed a haircut. `Anything Saffia wants, Saffia will get!' He seemed furious, but reined it in.

`This stinks,' I said quietly. More and more I saw him as the wronged son, whose father had had an adulterous relationship with his wife. It left a very unpleasant question mark over the paternity of Saffia's unborn child.

`Oh yes! She has bled me dry. Now she is making a dramatic fuss about a few unnecessary bedclothes, although believe me, Saffia has plenty – plenty of everything nowadays.'

The bed in his own room here remained fully equipped with covers. `Did you and Saffia share a bedroom?'

`Not during her pregnancy. She had a boudoir next door -'

I went and looked; the room was a shell. `She's stripped out everything that would move, I see.'

`She would have us hack off the frescos,' Birdy said, `but that would lower the value of this house when she comes to sell it!'

`You are clinging to your sense of decency.' I did not understand it though I admired his stoicism.

`She was my wife, Falco. I made a mistake there, but I live with its consequences. She is the mother of my children.' He never raised doubts over their paternity, I noticed. `Oh, she ensured that I had children,' he exclaimed grimly. `We are permanently tied together. And I tell myself,' he reasoned, with more feeling than I ever heard from him, `that if I always respond courteously to each indignity this woman hurls at me, that is my one chance!'

One chance for what? More than a quiet life, by the sound of it. I dropped my voice. `So you are a man charged with parricide – but you're hunting for pillows?'

`Pillows,' he raged. `Bolster, under-sheet, mattress – and her damned down-padded, peacock-embroidered coverlet.'

He did not have to hunt for long. The steward returned with news of the lost items. Perseus, the door porter, had appropriated them. Metellus Negrinus let out a furious exclamation, then strode to the slaves' quarters and robustly set about retrieval.

The porter was taking his ease in his cubicle, reclining on a decent mattress which he had put on the ledge in place of a slave's thin pallet. He had surrounded himself with knick-knacks, all stolen property, I suspected. Well, Saffia Donata was to have hers returned, though I myself would not have been keen on bedding that had been used by a leering and obnoxious house slave.

Maybe she deserved that. Anyway, Negrinus threw the porter off and began to haul the mattress up through the slaves' corridor to the atrium. I brought the pillows and linen for him. The steward, waiting in the atrium, began to rebuke Perseus.

`Leave him to me!' snarled Birdy. This was a revelation. He dropped the mattress on my feet; I jumped back. Negrinus grabbed Perseus by the tunic, glancing at it briefly and swore, as if he recognised the garment as one of his own. It was closely woven green wool, with ribbed braid at the neck, an expensive item. Clearly this porter lifted anything he fancied. The steward, who mostly seemed so efficient, looked powerless in his company.