'Gordianus, your son is an apt pupil. A better listener I've never encountered. I do believe the boy may have some talent for engineering.'

'Really?' I glanced over the fat man's shoulder at Eco, who looked quite bored. No doubt his thoughts were in a more briny milieu, floating across the seascape of the women's anteroom with Olympias. 'I've always thought so myself, Sergius Orata.

No doubt he finds it difficult to pose complicated questions, but I seem to remember yesterday that he was most curious about how the waters were disposed of after circulating through the pools. I told him I assumed some system of pipes led down to the bay, but my explanation failed to satisfy him.'

'Oh, yes?' Orata looked pleased. Eco stared at me, perplexed, then perceived the wink I gave him when Orata's back was turned. 'Then I shall have to explain it to him in detail, and leave nothing out. Come along, young man.' Orata disappeared through the door, and Eco trudged after him.

Metrobius laughed, then grunted as the slave Mollio recommenced pinching and pounding his flesh. 'Sergius Orata isn't quite the simple soul he pretends to be,' he said with a wry smile. 'There's quite a head on those shoulders, always calculating and counting his profits. He's certainly rich enough, and rumours allude to a weakness for gambling and dancing girls. Still, in this house he must seem a paragon of virtue – neither as greedy as Crassus nor as wicked as Mummius, not by a long shot.'

'About Crassus I know very little,' I confessed, 'only what they say behind his back in the Forum.'

'Believe every word. Really, I'm surprised he hasn't stolen the coin from the corpse's mouth.'

'As for Mummius-'

'The swine.'

'He seems an odd mix of a man to me. I'll grant you that there's harsh side to him. I saw an example of it on the journey here: for a drill, he ordered the galley slaves driven to the maximum – as frightening a spectacle as I've ever witnessed.'

'That sounds like Mummius, with his stupid military discipline. Discipline is a god he uses to excuse any act of wickedness, no matter how vile, just as Crassus can justify any crime for the sake of acquisition. They're two faces of a coin, opposites in many ways but essentially alike.' Such criticism struck me as odd, coming from a man who had been so closely allied with Sulla. But as the Etruscans say, love turns a blind eye to corruption, while jealousy sees every vice.

'And yet,' I said, 'I think I glimpse in both of them a certain weakness, a softness that shows through their armour. Mummius's armour is of steel, Crassus's is of silver, but why does any man cover himself with armour except to shield his vulnerability?'

Metrobius raised an eyebrow and looked at me shrewdly. 'Well, Gordianus of Rome, you may be more perceptive than I thought. What are these weaknesses evinced by Crassus and his lieutenant?'

I shrugged. 'I don't yet know enough about either of them to say.'

Metrobius nodded. 'Search and you may find, Finder. But enough about those two.' He rolled over and allowed the slave to stretch his arms above his head. 'Let's change the subject.'

'Perhaps you could tell me something about Lucius and Gelina. I understand that you and Gelina are very close friends.'

'We are.'

'And Lucius?'

'Didn't you just come from viewing Iaia's painted room?' 'Yes.'

'Then you must have seen his portrait.' 'Oh?'

'The jellyfish, just above the door.' 'What? Oh, I see, you're joking.'

'I'm not. Have a good look at it the next chance you get. The body is that of a jellyfish, but the face is quite unmistakably Lucius. It's in the eyes. A brilliant piece of satire, all the more satisfying because Lucius himself would never have got the joke. It elevates the whole mural to the level of high art. Iaia was once called the finest portraitist in Rome, and for good reason.'

'Then Lucius was a jellyfish?'

He snorted. 'A more useless man I never met. A mere footrest for Crassus, though a footrest might have had more personality. He's better off dead than alive.'

'Yet Gelina loved him.'

'Did she? Yes, I suppose she did. "Love turns a blind eye," as the Etruscans say.'

'I was just thinking of that proverb myself. But I suppose Gelina is by nature an emotional woman. She certainly seems distraught about the fate of her slaves.'

, He shrugged. 'If Crassus insists on killing them, it's a stupid waste, but I'm sure he'll give her others. Crassus owns more slaves than there are fish in the sea.'

'It impresses me that Gelina was able to convince Crassus to send a ship for me.'

'Gelina?' Metrobius smiled oddly. 'Yes, it was Gelina who first mentioned your name, but by herself I doubt that she could have talked Crassus into going to so much effort and expense on account of mere slaves.'

'What do you mean?'

'I thought you knew. There is another who longs to see these slaves plucked from the jaws of death.' 'Whom do you mean?'

'Who journeyed all the way to Rome just to fetch you?'

'Marcus Mummius? A man who would drive a whole ship of slaves to the point of death on a mere whim? Why would he lift a finger to save Gelina's slaves, especially in defiance of Crassus's will?'

Metrobius looked at me oddly. 'I thought surely you knew. When you spoke of Mummius having a weakness…' He frowned. 'You disappoint me, Finder. I think perhaps you are as dense as I originally thought. You were sitting beside me at dinner last night. You saw as clearly as I did the tears that sprang from Mummius's eyes when the slave boy sang. Do you think he wept for cheap sentiment? A man like Mummius weeps only because his heart is breaking.'

'You mean-'

'The other day, when Crassus made up his mind that the slaves should die, they argued and argued. Mummius was practically on his knees, begging Crassus to make an exception. But Crassus insists that they shall all be punished, including the beautiful Apollonius, no matter how harmless or innocent the boy may be, and no matter how much Mummius desires him. And so, the day after the funeral, Marcus Mummius will have to watch as his own men herd the boy into the arena and put him to death along with the rest of the household slaves. I wonder if they'll behead them one by one? Surely not, it would take all afternoon, and even a jaded Baian audience would start to fidget. Perhaps they'll have the gladiators do the dirty work, trapping the slaves under nets and rushing at them with spears

'Then Mummius wishes to save them all, simply for the sake of Apollonius?'

'Of course. He's quite willing to make a fool of himself on the boy's behalf. It all began on his last visit here with Crassus, back in the spring. Mummius was instantly smitten, like a stag struck with an arrow between the eyes. During the summer he actually wrote the boy a letter from Rome. Lucius intercepted it and was quite disgusted.'

'Because the letter was pornographic?'

'Pornography, from Mummius? Please, I'm sure he has neither the imagination nor the literary skill. On the contrary, it was quite chaste and cautious, rather like an epistle from Plato to one of his students, full of pious praise for Apollonius's spiritual wisdom and his transcendent beauty, that sort of thing.'

'But Lucius married for love. I should think he might have sympathized.'

'It was the impropriety of it that scandalized Lucius. A citizen consorting with one of his own slaves is one thing; it need never be known. But a citizen writing letters to another man's slave is an embarrassment to everyone. Lucius complained to Crassus, who must have said something to Mummius, since there was never a second letter. But Mummius remained smitten. He wanted to buy Apollonius for himself, but to do that required going through both Lucius and Crassus. One or the other refused to sell – perhaps Lucius, to spite Mummius, or perhaps Crassus, wanting to avoid further embarrassments from his lieutenant.'