Everywhere I looked I saw more and more of them – men, women, and children, all the slaves who had been gathered up from the fields or released from unnecessary tasks in the house and locked away to await the judgment of Crassus.

They sat huddled against the walls. I passed between them, walking the length of the long, narrow room. Eco followed behind me, gazing wide-eyed from face to face and tripping against the uneven floor. The smell of urine and waste grew stronger at the farther end of the room. The slaves forced to sit nearby huddled as far as they could from the stench. Exposed to it day after day, they must have grown used to it, enough to bear it. I covered my face with a fold of my heavy funeral garb, and still I could hardly breathe.

I felt a tug at my knee. Meto gazed up at me gravely. 'The best swimmer there ever was,' he assured me with a whisper. 'Better than Leander, and he could swim across the Hellespont. Better than Glaucus when he swam after Scylla, and Glaucus was half fish!'

No good it will do us if he's locked away here, I thought. Then I saw the young man at whom Meto pointed. The youth knelt on the straw, holding an old man's hands in his own and speaking in a low voice. The pale light gave his face a marmoreal smoothness, so that he looked more than ever like a statue come to life, or a living youth turned to stone.

'Apollonius,' I said, surprised to see him here.

He gave the old man's hands a final clasp, then stood and brushed the straw from his knees. The simple motion was as elegant as a poem. There is the haughty, manmade aristocracy of patricians like Faustus Fabius, I thought, and then there is the natural aristocracy of specimens such as this, which proceeds from the gods without regard to earthly status.

'Why are you here?' I asked, thinking Crassus must have banished him from the house simply to spite Mummius. But his explanation was simple.

'Most of the slaves have been locked away here since the day the master was found dead. A few of us have been allowed to stay at our posts, sleeping in our usual quarters between the stables and the house. Like Meto, I come here as often as I can, to see the others. The guards know me and let me pass.'

'Is he your father?' I said, looking down at the old man.

Apollonius smiled, but his eyes looked sad. 'I never had a father. Soterus knows herbs and poultices. He tends the other slaves when they're sick, but now he's sick himself. He craves water but can't drink, and his bowels are loose. Look, I think he's sleeping now. Once when I had a bad fever he tended to me night and day. He saved my life that summer. And all for nothing.'

I could discern no bitterness in his voice, no emotion at all. It was like the voice of his namesake, dispassionate and mysterious.

I held the cloth to my face and tried to catch a breath. 'Can you swim?' I asked, remembering why I had come.

Apollonius smiled a genuine smile. 'Like a dolphin,' he said.

There was a path which started just south of the annexe and led down to the boathouse, switching back and forth down the steep hill below the southern wing and the baths. The path was largely invisible from the house, hidden by high foliage and the steep angle of the hillside. It was a cruder path than the one I had taken down from the terrace at the north wing, but it was well-trampled and in most places wide enough for two to walk abreast. The boy Meto led the way, leaping over tree roots and scrambling down rock shelves. Eco and I descended at a more careful pace, while Apollonius followed deferentially behind us.

It was the warmest, sleepiest hour of the day. As we neared the boathouse I gazed up toward the hills, thinking of the funeral congregation forced to stand for hours while the flames slowly disintegrated all that remained of Lucius Licinius. I could see the tiny column of smoke rising above the treetops, thick and white but quickly blown into tattered streamers by the sea breeze, vanishing altogether as it dispersed into the blue above.

The little navy of boats moored at the pier knocked quietly against one another. As we stepped onto the pier, I noticed only a few dozing figures lounging in the boats, their feet dangling in the water and their faces covered by broad-brimmed sailors' hats. Most of the ferrymen and slaves had gone off scavenging for food, following the scent of roasting meats from the kitchens above, or else had slipped off to nap between the trees on the shady hillside.

'What did you lose?' asked Apollonius, peering down into the clear water in the open space between two of the boats. 'It's not exactly that I've lost something…' 'But what am I to look for?'

'I don't really know. Something heavy enough to make a loud splash. Perhaps several such objects.'

He looked at me dubiously, then shrugged. 'The water could be clearer, but I suppose most of the silt stirred up by all these boats arriving will have settled by now. And I could use more sunlight; all these boats together cast a great shadow over the bottom. But if I see anything that shouldn't be there, I'll bring it up to you.'

He unbelted and stripped off his tunic, then pulled his undertunic over his head and stood naked, his tousled hair glinting blue-black in the sunlight while lozenges of light, reflected off the water, danced across the sleek muscles of his chest and legs. Eco looked at him with a mixture of curiosity and envy. From beneath a broad-brimmed hat, one of the sailors made a crude but appreciative whistle. Apollonius lifted an eyebrow, but otherwise he ignored die sound; long ago he must have grown used to having others take note of his appearance.

He squared his shoulders and drew several deep breaths, then found a spot with room enough to dive into the water between two boats. The surface barely rippled behind him.

I strode up and down the jetty, peering into the green depths and catching glimpses of his naked whiteness as he darted amid the mossy stones and the wooden beams. In the water he propelled himself as gracefully as he moved on land, kicking with both legs in unison and using his arms as if they were wings.

A gull flew overhead. The column of smoke from the faraway funeral pyre continued to rise above the trees. Still Apollonius remained beneath the water. At last I saw his face gazing up at me from the murky bottom, then grow larger and larger as he propelled himself upward and at last broke through the surface.

I began to ask him what he had seen, but he gasped and held up his hand. He needed to breathe, not speak. Gradually his breathing grew slower and more regular. Finally he opened his mouth – to speak, I thought, but instead he sucked in a deep breath, bent his body double, and plunged beneath the surface again. His kicking feet left a spume of tiny bubbles behind.

He dived straight down, disappearing into the darkness. I walked up and down the pier, gazing over the edge. The gull circled, the smoke rose, a cloud rolled across the sun. By now the dozing figures in the boats had all awakened and were curiously watching us from beneath their hats.

'He's been under a long time,' one of them finally said.

'Very long,' said another, 'even for such a big-chested-boy.'

'Ah, it's nothing,' said a third. 'My brother dives for pearls, and he can stay down twice as long as this one's been under.'

'Even so…'

I looked between the boats, trying to see if he had come up in a hidden spot, wondering if he had struck his head. It had been a bad time to demand this task of him, with so many boats moored at the dock. Apollonius himself had complained of the dark shadow covering the bottom; even dolphins must need light to swim by. No matter what the pearl diver's brother might claim, it hardly seemed possible that a man could stay underwater as long as Apollonius had been gone.