I tried to sleep, but without much success. The creaking of manacles, the sluicing of the oars through the water, and the unending churning of the river against the bottom of the barge finally lulled me into fitful half-sleep, from which I woke over and over, always to the sound of Marcus Mummius's snoring. The fourth time I awoke to the raucous noise I poked my foot from under my blankets and gave him a gentle kick. He stopped for a moment and then resumed, making noises like a man slowly being strangled to death. I heard low chuckles of laughter and rose on my elbows to see his two guardsmen smiling back at me from the prow. They stood close together, talking quietly, wide awake. I looked behind and saw the helmsman at his station, a bearded giant who seemed to see and hear nothing but the river. Eco crouched nearby, gazing over the low bulwark into the water, looking like a statue of Narcissus contemplating his reflection beneath the starry sky.

Eventually Mummius's snoring quieted and blended with the slapping of water on wood and the steady, rhythmic breathing of the rowers, but still the deep, healing embrace of Morpheus eluded me. I tossed and turned uneasily inside the blankets, too hot and then too cold, my thoughts straying down blind alleys and doubling back on themselves. Dozing brought sluggishness without rest, stillness without refreshment; when we at last reached Ostia and the sea, I was a duller man than the one Marcus Mummius had lured from his bed some hours before. In the strange disjuncture of time and space that clouded my mind I imagined that the night would never end and we would journey in darkness forever.

Mummius ushered us from the barge onto a pier. The bodyguards came with us, but the rowers were left behind, gasping and bent double over their oars in exhaustion. I glanced back for a moment at their broad naked backs heaving and glinting with sweat in the starlight. One of them leaned over the bow and began to vomit. At some point during the journey I had stopped hearing their ragged breathing and the steady grating of the oars; I had forgotten them completely as one forgets the wheels of a grinding machine. Who notices a wheel until it needs oiling, or a slave until he turns sick or hungry or violent? I shivered and pulled the blanket around my shoulders to shut out the chilly sea air.

Mummius led us along the riverfront. Beneath the boardwalk I heard the soft lapping of waves against the wooden posts. To our right were clustered a fleet of small riverboats chained to the docks. To our left ran a low stone wall with crates and baskets piled against it in a wild confusion of shadows. Beyond the wall was the sleeping town of Ostia. Here and there I glimpsed the lit window of an upper storey, and at intervals there were lamps set into the city wall, but other than ourselves not a living person was stirring. The light played strange tricks; I imagined I saw a family of beggars huddled in a comer, then saw a rat come racing from the heap, which before my eyes resolved itself into nothing more than a pile of rags.

I tripped against a loose plank. Eco grabbed my shoulder to steady me, then Mummius almost knocked me down with a slap across the back. 'Didn't you sleep well enough?' he barked in his barracks voice. 'I can manage on two hours a day. In the army you learn to sleep standing up, even marching, if you have to.'

I nodded dully. We walked past warehouses and jetties, through shut-down markets and shipyards. The smell of salt grew stronger on the air, and the vague hissing of the sea joined with the steady lapping of the river. We came to the end of the docks, where the Tiber abruptly broadens and empties into the sea. The city wall swung away to the south, and a vast, starlit prospect of calm waters opened before us. Here another, larger boat awaited us. Mummius ushered us down the steps and into the hold. He barked at the overseer and the boat cast off.

The dock receded. The waves began to swell around us. Eco looked alarmed and clutched my sleeve. 'Don't worry,' I told him. 'We won't be on this boat for long.'

A moment later, as we navigated around a shallow, rocky promontory, the vessel came in sight. 'A trireme!' I whispered.

'The Fury, she's called,' said Mummius, seeing my surprise and smiling proudly.

I had expected a large ship, but nothing as large as this one. Three masts, their sails cowled, rose from the deck. Three rows of oars projected from her belly. It hardly seemed possible that such a hulking monster had been dispatched merely to fetch a single man. Mummius lit a torch and waved it over his head. A torch was lit on deck and waved back at us. As we drew nearer, men suddenly swarmed about the deck and up the masts, as quiet as ghosts in the starlight. The oars, retracted from the water, stirred like the quivering legs of a centipede and dipped downward. Sails unfurled and snapped taut in the soft breeze. Mummius wet his finger and held it aloft. 'Not much of a wind, but steady to the south. Good!'

We drew abreast. A rope ladder was lowered. Eco scrambled up first and I followed. Marcus Mummius came last and pulled up the ladder behind him. The smaller boat drew away, back toward Ostia. Mummius walked quickly up and down the length of the ship, giving orders. The Fury heaved and swung about. The steady rhythm of oarsmen groaning in unison rose up through the boards, and on either side there was a great splash as the first stroke sliced into the waves. I looked back at Ostia, at the narrow beach that fronted the city's shoreward side and the tiled rooftops that rose above the walls. The town receded with stunning speed; the walls dwindled, the gulf of dark water grew greater and greater. Rome suddenly seemed very far away.

Marcus Mummius, busy with the crew, ignored us. Eco and I found a quiet spot and did our best to sleep, leaning against each other and huddling in our blankets to shut out the chill of the open sea.

Suddenly Mummius was shaking me awake.

'What are you doing on deck? A pampered city dweller like you will take a fever and die from this damp air. Come on, both of you, there's a room for you at the stern.'

We followed him, stumbling over coils of rope and hidden hatches. The first rays of dawn were breaking over the dark hills to the east. Mummius led us down a short flight of steps and into a tiny room with two pallets, side by side. I fell onto the nearer one and shuddered at the pleasant shock of feeling myself submerged in a thick mattress of the finest goose down. Eco took the other and began to yawn and stretch like a cat. I pulled my blanket up around my neck, already half-asleep, and vaguely wondered if Mummius had allowed us to take his own accommodation.

I opened my eyes and saw him standing with his arms crossed, leaning against the wall in the hall outside. His face was barely visible in the pale light of dawn, but there could be no doubt, from the gende flutter of his eyelids and the slackness of his jaw, that Marcus Mummius, an honest soldier and no boaster, was fast asleep and dreaming, standing up.