`Falco! What are you doing here, and who's your big bodyguard?'

I walked forwards. `I act as his guardian actually, sir.' Petronius, annoyed at my joke, followed me; I shoved him to the front. `This is my friend Lucius Petronius Longus, whom you want to see: the enquiry captain of the Aventine sector in the Fourth Cohort of the vigiles. He's one of the best – but he's also the happy fellow who shut the Emporium today.'

Vespasian Augustus stared at Petronius. Petronius looked selfconscious, then thought better of it and stared boldly at the floor. It was marble; a tasteful acreage in black and white. The tesselations had been laid by a sharp tiler.

`That took nerve!' commented the Emperor. Petronius looked up again, and grinned slightly. He would be all right. I folded my arms and beamed at him like a proud trainer showing off his best gladiator.

`I apologise for any inconvenience, sir.' Petronius always sounded good. He had a mellow voice and a calm delivery. He gave a trustworthy impression. That explained his success with civic selection boards,, and with women.

`Apologies may not be enough,' replied Vespasian. Unlike selection boards and women, he could spot a rogue. `How do you know Falco?'

`Colleagues from the Second Augusta, sir.' Our legion was one Vespasian himself had once led. Both Petro and I allowed ourselves a certain cockiness.

`Really.' The Second had disgraced itself since Vespasian's day. Regretfully, we all let the subject drop. `You two work in different areas now.'

`We both strive for law and order, sir.' A bit too pious, I thought. Petro could get away with it perhaps, since Vespasian had not known him long. `Which is what I was doing today after the robbery at the Emporium.' Petronius liked to gallop straight to the point. The concept of first being weighed up through friendly chatter was so alien to his blunt nature that he was rushing the interview.

`You wanted to assess the damage before people trampled everywhere.' Vespasian could assimilate information swiftly; he rapped out the explanation as if it were obvious. I saw Petro flush slightly. He now realised he had plunged in too fast. Given our relative positions in this conversation, forcing the pace was rude. Being rude to an Emperor was the first step to having a lion sniff your bum. `Why', asked the Emperor coolly, `could you not have made the merchants responsible for alerting you to their losses in due course? It is in their own interests to provide the information. They will want you to retrieve the stolen goods. So why cause a riot?'

Petronius looked alarmed. He had done things his own way. It was a way that would work, so he had not bothered with alternatives. Alternatives tend to be messy. Just thinking about them wastes time.

`Closing the market sounds crude,' he admitted. `I was thinking ahead, sir. It was clear we were dealing with a highly organised gang. They had already made fools of everyone involved with security at the Emporium.' He paused. Vespasian quietly indicated that he could go on. Petro got into his stride: `My immediate reaction was that the raid was so well done they wouldn't stop there. We'll see them again – either at the Emporium, or elsewhere. At this moment they have the advantage of me. I need all the facts – and I need them rapidly. Today I had to discover everything I could about the methods used – how they had identified the goods in advance, for instance. This was no ordinary robbery. The haul was exceptional, and I prophesy big trouble in Rome.'

Without actually answering the original question, Petronius Longus had managed to put the situation in context. He came out of it well, too. I knew it was bluff, but he looked like a man who was planning well.

`You expect a repetition of today?'

`I fear it, sir.'

The Emperor leant forwards suddenly. `Were you expecting this?'

Petronius did not flinch from the fierce question. `No sir. But I had felt something might happen.'

`Why?'

`A power vacuum has been created in the criminal fraternity.' `How? Oh, Balbinus Pius of course. You were responsible for that.'

This time Petro was startled. He had not realised that the tablet which Vespasian had been reading when we entered would have been his brief from the secretariat: a swift summary of events today, an account of Petro's career, a resume of the Balbinus case, even polite suggestions for handling this interview.

I stepped in: `Petronius Longus is too modest to regale you with his success, sir. He was indeed the officer who convicted Balbinus. He found an opportunity to do it, and he saw matters through. He's too good a man to stop there. He thought ahead, and considered the effect on Rome.'

Vespasian gave no sign of having heard me, though he certainly had. He looked at Petro, who was quite capable of sliding out of this. While I burbled, he had already marshalled his thoughts: `Sir, I realised the size of the Emporium heist meant there would be political implications.'

`Political?' We had the Emperor's full attention. He himself had stepped into a power vacuum when he wrested the throne from the various contenders and settled in to remedy the oddities of Nero's reign and the devastation of the ensuing civil war. He had yet to prove himself. He was working hard, but the benefits of good government take longer than the ravages of bad to become apparent. His grasp on power was still precarious.

I suggested dryly, `Robbery on a grand scale casts doubt upon the government's effectiveness, sir.'

`No, it casts doubt on the effectiveness of the watch!' retorted the Emperor.

Petronius was visibly annoyed with me. `Sir, it will cause grumbles, I realise. But I take this theft as a signal. It was very bold. Some element is declaring open war -'

`On whom?' rapped the Emperor. `You? Me?'

'On the watch, certainly,' Petro replied slowly. `On the state by implication. And probably on other major thieves. Given that context, I should say that it is likely to involve more than one city sector -'

`That's beyond your scope!' Vespasian had an old-fashioned regard for the limits of office. Immediately he reined Petro in:

`That calls for a co-ordinated strategy.'

`Yes, sir,' agreed Petronius, looking meek. `I was of course intending to alert my cohort tribune and the Prefect of the City, sir.' The lying shark!

Vespasian thought about it. `I'd better see your tribune. I'd better see them all.' He gave a slight nod to some sideliner in a white tunic. This silent, virtually invisible official was more than just a secretary. Notes were being made briefly on a tablet, but these were the notes of a man taking instructions. He knew the first rule of administration: always cover yourself. `Conference After lunch. Warn Titus.' The Emperor spoke off-handedly, though both Petro and I had a sense of starting far more than we had bargained for. He turned back to us. `That still leaves the riot to diffuse. What do you suggest?'

Knowing that the man who starts a riot rarely thinks about how he will stop it, I thought best to offer ideas myself. `You could mollify the discontent to some degree by announcing compensation, sir.'

`Compensation?'

I had done it now. I had used a naughty word.