"Outside the city walls?"

"Yes. That way I can attend – legally attend – the proceedings. Let no man say that Pompey thinks himself above the law! A lot of business has piled up, as you can imagine. A number of proposals shall be put forth. One of them is to rebuild the Senate House. No controversy there. I shall suggest that Milo's brother-in-law Faustus Sulla be given the contract. Let no man say that Pompey is unfair to the relatives of Milo! Besides, such a commission seems only proper, since it was Sulla, Faustus's father, who remodelled the old Senate House. Thus the Senate shall pay homage to the memory of the dictator Sulla and his achievements. Many Romans flinch at that word, dictator. They forget how important it is to have some mechanism whereby supreme power can be placed in the hands of a single man, when circumstances demand it."

He took another sip of wine and stared at the pillars of smoke as if he could disperse them by sheer will power. "And there will be another, more important proposal – that the Senate declare a state of emergency and issue the Ultimate Decree. Do you know what that means, Finder?"

"Yes," I said, remembering the last time such a decree had been issued, when Cicero was consul and had demanded extraordinary powers to deal with Catilina and his circle. "The Ultimate Decree instructs the consuls to do 'whatever may be necessary to save the state.' "

"Martial law," said Pompey, bluntly. "But there are no consuls."

"Yes, that's a problem. How can troops be levied from the countryside if there are no consuls to levy them? Well, it's only a technicality, really. Someone other than a consul will have to do the job, of course. Fortunately, as a man who has twice been elected consul and as the current commander of the Roman troops in Spain, I have both the necessary expertise to raise a militia here in Italy, and the skill to deploy it in the most efficient manner to bring order to the city."

"The Senate will agree to this?"

"I'm certain they will. It's all a matter of counting the votes ahead of time. Oh, some of Caesar's supporters will make a fuss, as may some of the more hidebound conservatives, like Cato. A terrible precedent, they shall say, but what other solution have they to offer? They won't protest too vehemently. I shall find ways to mollify them. The important thing is that order be restored. If we must resort to certain innovations to achieve that end, if the law must be slightly bent, then so be it."

He at last turned his gaze from the pillars of smoke, which, for the moment at least, had refused to disperse. "Well then, shall we discuss your fee, Finder?"

A man commences a journey on the Appian Way with the smell of fish in his nostrils and the sound of dripping water in his ears.

The smell comes from the fish markets just outside the Capena Gate, at the southern end of the city. Fishermen from the Tiber and as far away as Ostia string up their catches on lines, presenting row upon row of fish hung up by their gaping jaws, with here and there a basket full of molluscs, octopi or squid. On a normal day, at a normal hour, the place resounds with the jabber of kitchen slaves, housewives and marketers. We set out in the grey hour before dawn, before the markets would normally be open, but even so the place was unnaturally quiet and deserted. According to Bethesda, there had been no market outside the Capena Gate for days. Like startled minnows, the fishermen had all been scared away. Still, there was a strong odour of fish about the place, as if the sea had penetrated the very stones beneath our feet.

The sound of dripping water comes from a leak in the Appian aqueduct. It was built by the same Appius Claudius Caecus who built the Appian Way, two hundred and sixty yean ago. When the aqueduct reaches the city it merges with the wall and for a considerable distance flows inside it, a river within a wall, a marvel of design and engineering spoiled by only one defect: at the Capena Gate, the aqueduct leaks. In warm months the great arching blocks of stone overhead are covered with dripping moss, like the ceiling of a grotto. In the dead of winter the moss dies back and sometimes the water freezes into a dully gleaming sheet of ice. On this morning it was not that cold. The water seeped, slowly but freely. As we stepped through the gate, one drop in particular, an especially large, especially frigid drop, struck the back of my neck and wriggled down my spine. I gave a jerk and must have made a curious noise, for Eco gripped my arm and Davus looked at me with alarm.

I knew what Davus must be thinking: it's an ill omen to begin the first step of a journey with a shudder and a curse from the master. Eco, less superstitious, probably feared that I was having a seizure. Then a drop glanced off the tip of Eco's nose, making him blink in confusion. When Davus tilted his head back and opened his mouth to laugh, another drop struck him square between the eyes.

"There, now we've all been anointed by the Capena Gate. A very good omen," I declared for the benefit of Davus.

Eco raised a dubious eyebrow. "Where is this stable that Pompey mentioned? I've never noticed it before."

I looked around. Towards the left, just beyond the market, stood the dense grove of trees that surrounded the shrine of Egeria with its limestone springs. It could hardly be in that direction. I looked towards the right. "That must be the place, over there. It looks like a stable, doesn't it? Usually all the hanging fish would hide it from view. I see an open door and a light inside. Someone must be up already."

A narrow path flanked by cypress trees led to the long, low building in the shadow of the city wall. I took a step inside the open door and was met by an odour of horse dung and hay that was a welcome relief to the stink offish, then by a pitchfork aimed at my throat.

"Who are you? What do you want?" The man held a lamp in his other hand. The glow lit up his gaunt, wary face.

"We come from your master," I said. "I thought you'd be expecting us."

"Maybe. What are you called?"

"Finder."

"All right, then." The man lowered his pitchfork. "I have to be careful. There's been a lot of trouble lately. Desperate men, damned good horses, and me in between – me the one who'll pay if there's any stolen. Understand? And I'll tell you, the master keeps some fine ones here. Fine horses! Takes a military man to really appreciate what a horse is worth. Keeps them here for convenience, for when he wants to take a ride to his villa down south. Come along and see. Careful, follow the lamp. He said you could have your pick. How many are you? Three? Here, I happen to have three blacks, not a spot of white on them. Those are the ones I'd take if I were you."

I saw the three he meant and reached towards the nearest. The beast had a long, powerful neck and bright eyes. "Why? Are these the fastest?"

He shrugged. "Maybe, maybe not. But they'd for sure be the hardest to see if you do any riding after dark. Something to think about, these days, making yourself hard to see if you're out in the open at night."

The three horses looked fit and strong enough, and were very black indeed; even in the glow of the man's lamp they tended to vanish into the shadowy stalls. I took his advice.

Davus had some trouble mounting his horse. It turned out he had never ridden a horse before.

Eco looked thoroughly disgusted – not angry at Davus but at himself for not thinking of such an elementary detail before we set out. What use was a bodyguard on horseback if he couldn't control his mount? Davus was now my personal bodyguard; I should have been the one to ask if he could ride, but I was so used to Belbo that I took it for granted. "You've never even been on a horse?" I asked.