`Not the old "present to wife's brother" trick?'

He gave me a respectful gleam. `Haven't come across that one! No: "dowry to daughter's husband".'

I shook my head. `Met it before. I took a jurist's advice and the news is bad: you can't touch the coinage. So long as the marriage lasts it has passed away from the family. Title to the dowry goes with the title to the girl. The husband owns both, with no legal responsibility to the father-in-law.'

`Maybe they'll divorce!' sneered the ex-rent-collector, in a tone that suggested heavy whacks might be used to end the marriage. Once a muscleman, always a thug.

`If the dowry was big enough, love will triumph,' I warned. `Cash in hand tends to make husbands romantic.'

`Then I'll have to explain to the girl that her husband's an empty conker shell.'

`Oh I think she must have noticed that!' Fusculus put in. He glanced at me, promising to elaborate on the gossip later.

I saw Nonnius looking between us, trying to work out how Fusculus and I were in league. None of the vigiles wore uniforms. The foot patrols were kitted out in red tunics as a livery to help them force a right of way to the fountains during a fire, but Petro's agents dressed much as he did, in dark colours with only a whip or cudgel to reveal their status, and with boots that were tough enough to serve as an extra weapon. They and I were indistinguishable. I wore my normal work clothes too: a tunic the colour of mushroom gravy, a liverish belt, and boots that knew their way around.

The room was full of working boots. There were enough soles and studs to subdue a crowd of rioting fishmongers in five minutes flat. Only the slave boy, in his embroidered Persian slippers, failed to match up to the rest of us.

`What's your background?' Nonnius demanded of me, bluntly suspicious.

`I'm an informer basically. I take on specials for the Emperor.'

`That stinks!'

`Not as much as enforcing for organised crime!'

I was pleased to see he did not care for me standing up to him. His tone became peevish. `If you've finished insulting me, I've got enough to do chasing my stake from the Balbinus case.'

`Stay busy!' I advised.

He laughed briefly. `I gather your "roving commission" will not include helping me!'

I wanted to tackle the area that Rubella had called past history; the one that had big implications for the future. `I need to rove in other directions.'

`What do you want with me?'

`Information.'

`Of course. You're an informer! Are you buying?' he tried brazenly.

`Not from a jury fixer!'

`So what are you looking for, Falco?' Nonnius asked, ignoring the insult this time as he tried to startle me.

I could play that game. `Whether it's you who masterminded the Emporium heist.'

It failed to nettle him. `I heard about that,' he said softly. So had most of Rome, so I couldn't accuse him of unnatural inside knowledge. Not yet anyway. I was starting to feel that if he had been involved, handing him over to justice would give me great pleasure. I had a distinct feeling that he knew more than he ought. But crooks enjoy making you feel that.

`Somebody could hardly wait for Balbinus to leave town,' I told him. `They snatched the inside lane of the racecourse – and they want everyone to know who's driving to win.'

`Looks that way,' he agreed, like a convivial friend humouring me.

`Was it you?'

`I'm a sick man.'

`As I said earlier,' I smiled, `I'm very sorry to hear that, Nonnius Albius… I've been away. I missed your famous court appearance, so let's run over a few things.'

He looked sulky. 'I said my piece and I'm finished.'

`Oh yes. I heard you're quite an orator -'

At this point Fusculus, who had been watching with amused patience, suddenly cracked with anger and had to butt in: `Get a grindstone and sharpen up, Nonnius! You're a committed songbird now. Tell the man what he needs to know!'

`Or what?' jeered the patient, showing us the ugly glower that must have been forced on countless debtors. `I'm dying. You can't frighten me.'

'We all die,' Fusculus replied. He was a quiet, calm philosopher. `Some of us try to avoid being hung up in chains in the Banqueting Chamber first, while Sergius gives his whip an airing.'

Nonnius was hard to terrify. He had probably devised and carried out more excruciating tortures than we two innocents could even imagine. `Forget it, shave-tail! That's the frightener you use for schoolboys filching oysters off barrows.' He glared at Fusculus suddenly. `I know you!'

`I've been involved in the Balbinus case.'

`Oh yes, one of the Fourth Cohort's brave esparto-grass boys!' This was the traditional rude nickname for the foot patrols, after the mats they were issued with for smothering blazes. Used of Petro's team, who thought themselves above firefighting, it was doubly rude. (All the worse because the esparto mats were regarded as useless anyway.)

I managed to break in before things got too hot. `Tell me about how the Balbinus empire worked.'

`A pleasure,. young man!' Nonnius decided to treat me as the reasonable person in our party in order to show up Fusculus. The latter settled back again, quite content to simmer down. `What do you want, Falco?'

`I know Balbinus was the uncrowned king of rat thieves and porch-crawlers. He ran small-time crime as an industry and had drop shops on every street corner to process the loot. I haven't even mentioned the brothels or the illicit gaming houses yet -'

`He could run an estate,' Nonnius conceded, with visible pride at being an associate.

`With your help'. He accepted the smarm. I choked back my disgust. `It was more than stealing scarves from washing lines, however.'

`Balbinus was big enough to have carried off the Emporium raid,' Nonnius agreed. `Were he still in Rome!'

`But sadly he's travelling… So who might have inherited his talent? We'll take it that you personally have retired to lead a blameless life.' Nonnius allowed that lie too. `Were there any other big boys in the gang who could be showing a flash presence now?'

`Your sidekick ought to know names,' Nonnius sneered nastily. `He helped close down the show!'

Fusculus acknowledged it with his normal grace, refusing to lose his temper this time. `They all had cheap nicknames,' he said quietly to me, before running off one of his competent lists: `The Miller was the most sordid; he did the killings. The more brutal, the more he liked it. Little Icarus thought he could fly above the rest, the joke being that he was a complete no-hoper: Same for Julius Caesar. He was one of those madmen who think they're an emperor. Laurels would get the blight pretty quickly on his greasy head. The others I knew were called Verdigris and the Fly.'

We looked at Nonnius for confirmation; he shrugged, pretending at last to be impressed. `Clever boy!'

`And where are they all now?' I asked.

`All gone to the country when the trial came off.'

`Quiet holidays in Latium? You reckon that's true?' I put to Fusculus.

He nodded. `Minding goats.'

Petro would have kept tabs on them as far as possible. `So, Nonnius, those were the centurions, and now they're living in rural retirement like a legion's colony of veterans Who were the big rivals to your dirty group?'

`We did not allow rivals!'

I could believe that.

There was no need to press the point. Better to think about the other criminal gangs after we left him. I sensed that Nonnius was taking a gloating delight in my interest in the rivals – who undoubtedly existed, even though Balbinus Pius must have done his best to strong-arm them out of his territory. I saw no need to gratify the rent-collector's pernicious taste for making trouble.

`We'll be in touch,' I said, trying to make it sound worrying.

`Don't wait too long,' leered Nonnius. `I'm a sick man!'