'Gordianus, I never told Caelius to strong-arm you into having me. Caelius told me you were happy to do so.'

'But your riddle in the Senate, about the headless masses and the Senate with its withered body. The coincidence of the headless bodies on my farm…'

'Gordianus, are you telling me that all this time, you've hosted me only because Caelius forced you to? Well, there you have your villain. Someone told Cicero's henchmen to go looking for me on your farm last night: Caelius, obviously. He must have been loyal to Cicero all along. By Jupiter, when I think of the confidences I divulged to him…' He threw back his head with a pained expression. 'Gordianus, have you then no affection for my cause at all? Were you merely doing Caelius's bidding when you let me into your house?'

Now it was my turn to mirror his look of consternation. I might have said yes and not told a He, but the truth no longer seemed as simple as that.

'Never mind,' he said. 'The important thing is that you didn't betray me last night, when you had the chance. Unless—' He looked at the trailhead, and his face turned grey. 'Unless Tongilius and the others are descending into an ambush!'

He put his hand on the hilt of his sword. I felt a quiver of panic. He turned to me with murder in his eyes, and for the first time I saw the true depth of his despair. Lucius Sergius Catilina was a patrician, born into privilege and respectability. Trust was his birthright and highest value — trust in the gods, trust in the immutability of his station, trust in the high regard of his fellow citizens; trust, also, in the invincibility of his own innate charm. Now these layers of trust had been stripped away from him one by one; gods and men alike had betrayed him.

I laid my hand on his. I had to grit my teeth with the effort to keep his sword in its scabbard. 'No, Catilina, your men are safe. I haven't betrayed you! Think — Meto is with them. I wouldn't send my own son into a trap.'

He slowly relaxed. His lips registered a cracked smile. 'Do you see what's become of me?' He gazed towards the empty trailhead, as if he could still see the young men who had descended ahead of us. 'But they still look to me for strength, as they always have. Come, hurry!'

As I had feared, the way down was more treacherous than the way up. The trail was littered with the debris of twigs and branches, and the rain had turned the rigid earth into a treacherous soup of mud and stones. We descended as much by sliding as by stepping. We tumbled against each other and clutched at each other's arms, using the solidity of our bodies to gain a mutual balance against the unsteady elements. I banged my elbows and scraped my knees; I slipped and fell on my rump so many times it almost stopped hurting. The near-impossibility of the descent eventually took on an air of absurdity. From below us we heard the high-spirited whooping of Catilina's men, a warning of more slipping and sliding ahead. I braced myself for the final stretch, too out of breath to laugh.

At last we came to the stony clearing where the horses waited. The beasts looked ragged and miserable after their long night in the rain, but they nickered and shook themselves at the sight of Catilina's men, as eager to set out as their riders. Everyone was covered with mud, myself most of all.

'I've already had a look at the highway,' said Tongilius. 'The road is clear.'

We led our horses one by one through, the narrow passage between the boulder and the oak. To make up for the missing hone, I gave them my own. Meto and I mounted his horse together.

The exhilaration of the descent had restored Catilina's confidence. He clutched his reins and let his mount canter about. She stood upright on her hind legs and whinnied, happy to be out of the mud and muck. When he had calmed her, he came over to us, leaning forward to stroke the beast's neck. 'Are you sure you won't come with us, Gordianus? No, I'm only joking! Your place is here. You have a family. You have a future.'

He circled, waving for his men to form a bodyguard around him. How strange his company looked, filthy and ragged and yet wearing smiles as if they had just won some glorious battle. 'Tongilius, you have the silver eagle? Good. Gordianus, I thank you for what you've done. And for what you might have done against me but did not do, I thank you even more.'

He turned and rode away at a swift gallop. Meto and I followed him to the crest of the hill and watched the company for a long time as they grew smaller and smaller, vanishing into the north.

Meto said aloud what I was thinking: 'Will we ever see him again, Papa?'

I let my body answer — a twitch of the shoulders to form a non-committal shrug. Who but the Fates could answer such a question? Even so, I feared that we had seen the last of Catilina.

When we returned to the house, Diana was delighted, thinking we must have been out early playing in the mud. Bethesda was appalled, but also relieved, though she tried not to show it. Exhausted, I let her scrub me with a sponge and then crawled into my bed. At some point she joined me and made love to me with a consuming ferocity she had not shown in a long time.

On that very day — while I dozed, while Catilina and his company raced northwards — Cicero made a second speech against Catilina in Rome, not to the Senate but directly to the citizens assembled in the Forum. This I learned the next day from a slave who brought a letter from Eco, which warned me, too late, of Catilina's flight. The speech to the people reiterated much of what Cicero had said to the Senate, but with even greater venom and a crude hyperbole that showed no small contempt for his audience's sophistication. Eco made no comments on the speech — understandably, for what if the letter had fallen into other hands? — but instead quoted it at length. Perhaps he was as appalled as I was and thought that rendering Cicero's words verbatim would convey all that needed to be said, or perhaps he was merely amused at such outrageously inflammatory rhetoric, and transcribed it for my amusement.

In his speech Cicero announced Catilina's flight from Rome and humbly took credit for 'removing the dagger from our throat.' He then coyly acknowledged that some might fault him for not putting the scoundrel to death instead (though he could not have done so legally; only the courts and the people's Assembly have that right). Catilina's flight was proof of his guilt, and Cicero berated those who had been too stupid to see the truth before. If there were those who portrayed Catilina as a guiltless martyr and Cicero as his vengeful persecutor, then Cicero would bear the burden of such slander for the sake of saving Rome. As for those in league with Catilina who remained at large in the city, that band of perfumed and overdressed 'warriors' could hope to have no secrets from him; the consul's eyes and ears followed them everywhere, and he was aware of their innermost thoughts.

As for rumours that Catilina was headed for Massilia and exile rather than for Manlius and his soldiers, Cicero hoped it might be true but doubted it 'By Hercules, even if he were utterly innocent of traitorous designs, Catilina is precisely the sort of person who had rather die an outlaw's death than wither away in exile.' Cicero had gauged his opponent shrewdly.

He dwelt on Catilina's sex life repeatedly and at great length, calling him the world's most accomplished seducer of young men, mentioning Tongilius and others by name, and saying that Catilina made some of his conquests by murdering young men's parents at their request and thus sharing their inheritances even while he plundered their orifices. Catilina, Cicero said, was shameless in taking both the dominant and the subservient role. His once-famous attributes of physical endurance and energy had long ago been squandered in mindless orgies.