It was a mad day. Rome seemed racked with fever, delirious. With Clodius consigned to the purifying flames, and the Senate House along with him, his mourners carried on their unconventional funeral celebration. Could they have planned such madness in advance, or did they make it up as they went along, inspired by the dancing flames and the billowing smoke, invigorated by the charred tang in the air? At mid-afternoon, they held a funeral feast. Before the smouldering Senate House they set up tables, covered the tables with black cloths and spread out a banquet.

While the firefighters continued their frantic efforts, the Clodians drank and ate in honour of their dead leader. The poor and hungry of the city came out to join them, at first meekly and then, seeing that they were welcome, in jubilation. Vast quantities of food arrived -great urns full of blood-black sausages, pots of black beans, loaves of black bread, all suitably black for a feast to honour the dead, washed down with blood-red wine. Meanwhile the confused, frightened, curious citizens of Rome – those who lacked the safe vantage of a Palatine rooftop to watch what was going on – skirted the edges of the Forum, cautiously peeking around comers and peering over walls, gawking variously in outrage, delight, disbelief and consternation.

I spent much of the day on my root watching. So did Cicero. He would disappear for a while, then reappear with various visitors, many of them senators, as I could tell from the purple border on their togas. They would take in the view, shake their heads in disgust or gasp in horror, then disappear again, talking and gesticulating. There seemed to be some sort of all-day meeting going on in Cicero's house.

Eco came by to see me for a while. I told him he was mad to venture out on such a day. He had stayed clear of the Forum, and though he had heard the rumour that the Senate House was destroyed, he had thought it was only that, a rumour. I took him up on the.roof so he could see the spectacle for himself. He headed back to Menenia and the twins soon after.

Even Bethesda overcame her distrust of the ladder and ventured up on the roof for a while to see what all the fuss was about. I teased her that the sight of so much rioting must have made her homesick for Alexandria, seeing that the Alexandrians were so famous for rioting. She didn't laugh at the joke. Neither did I.

The feasting and the firefighting down in the Forum continued until well after nightfall. Towards evening Belbo brought me a bowl of hot soup and climbed back down. A little later Diana joined me with her own steaming bowl. As we sat alone on the roof the sky darkened to deeper and deeper shades of blue verging into black. In every season, twilight is the most beautiful hour in Rome. The stars began to show in the firmament, glittering like bits of frost. There was even a kind of prettiness about the nickering lights down in the Forum, now that darkness hid the ugliness of charred wood and blackened stone. The fires had largely died down, but the deepening gloom revealed smouldering patches of flame in the ruins of the Porcian Basilica and the senatorial office buildings.

Diana finished her soup. She put down the bowl and pulled a blanket over her shoulders. "How did Clodius die, Papa?"

"From his wounds, I should think: Surely you don't want me to describe them again."

"No. I mean, how did it happen?"

"I don't know, really. I'm not sure that anyone does, except whoever killed him, of course. There seemed to be quite a bit of confusion about it at his house last night. Clodia said there was a skirmish of some sort down on the Appian Way, near a place called Bovillae, where Clodius had a villa. Clodius and some of his men had an altercation with Milo and some of his men. Clodius got the worst of it."

"But why did they fight?"

"Clodius and Milo have been enemies for a long time, Diana." "Why?"

"Why are two men usually enemies? Because they want the same thing." "A woman?"

"In some cases. Or a boy. Or a father's love. Or an inheritance, or a piece of land. In this case, Clodius and Milo both wanted power." "And they couldn't both have it?"

" Apparently not. Sometimes when two ambitious men are enemies, one of them has to die if the other's to go on living. At least that's how it usually works out, sooner or later. It's what we Romans call politics." I smiled without mirth.

"You hate politics, don't you, Papa?" "I like to say I do." "But I thought -"

"I'm like the man who says he hates the theatre but never misses a play. He claims it's his friends who drag him along. Even so, he can quote every line of Terence."

"So you secretly love politics."

"No! But it's in the air I breathe, and I don't care to stop breathing. Put it another way: politics is the Roman disease, and I'm no more immune than anyone else."

She frowned. "What do you mean?"

"Certain diseases are peculiar to certain tribes and nations. Your brother Meto says that up in Gaul there's a tribe in which every person is born deaf in one ear. You've heard your mother say that there's a village on the Nile where everyone breaks out in hives at the approach of a cat. And I read once that Spaniards suffer a form of tooth rot that can only be cured by drinking their own urine."

"Papa!" Diana wrinkled her nose.

"Not all diseases are grossly physical. The Athenians are addicted to art; without it they become irritable and constipated. Alexandrians live for commerce; they'd sell a virgin's sigh if they could find a way to bottle it. I hear the Parthians suffer from hippomania; whole clans go to war with each other to lay claim to a fine breeding stud.

"Well, politics is the Roman disease. Everyone in the city catches it sooner or later, even women nowadays. No one ever recovers. It's an insidious sickness, with perverse symptoms. Different people suffer in different ways, and some don't suffer at all; it cripples one man, kills another, and makes yet another man grow fat and strong."

"So is it a good thing or a bad thing?"

"Just a Roman thing, Diana. And whether it's good or bad for Rome, I can't say. It's made us the rulers of the world. But I begin to wonder if it won't be the end of us." I stared down at the Forum, no longer like Jupiter watching the plain of Ida – more now like Pluto surveying the fiery pits of Hades.

Diana leaned back. Her jet-black hair made a pillow for her head as she studied the sky above. Her dark eyes reflected glimmers of cold starlight.

"I like it when you talk to me like this, Papa."

"Do you?"

"This is how you used to talk to Meto sometimes, before he left for the army."

"I suppose."

She turned on her side, propped her head on her hand and looked at me earnestly. "Is something bad going to happen, Papa?"

"I imagine the people around Clodius think something bad has already happened."

"To us, I mean. Are we in danger, Papa?"

"Not if I can help it." I ran my hand over the side of her face and stroked her hair.

"But things are getting worse, aren't they? That's what you and Eco always say to each other, when you talk politics. And now it's worse than ever – Clodius dead, the Senate House burned down. Is something awful about to happen?"

"Something awful is always about to happen – to someone, somewhere. The only escape is to make a friend of Fortune, if she'll have you, and run the other way whenever you see a politician coming."

"I'm serious, Papa. Are things about to – I don't know, about to fall apart? For us, for everybody?"

How could I answer her? Out of the past I suddenly remembered a scene from the Forum when I was a young man, after Sulla won the civil war: rows and rows of heads mounted on pikes, the enemies of the dictator paying gaping witness to his triumph. Afterwards, people swore that such a thing would never happen again. That was thirty years ago.