Along with the filth that smudged his cheeks and the suffering in his eyes, there was a strange look of innocence about him. His dark features were strikingly handsome, his prominent nose and mouth and wide dark eyes suggestive of the East. As I studied him in the moonlight, he dared to look back at me and then actually smiled – a sad, pathetic smile, tentative and fearful.

I thought of how easily Eco might have ended up in such a place if I had not found him and taken him home that day long ago – a boy with a strong body without a tongue or a family to defend himself might easily be waylaid and sold at auction. I looked back at the slave boy. I tried to smile in return, but could not.

Suddenly a man descended the stairs and pushed roughly past me, then hurried towards the stern. He shouted something and the drumbeat abruptly accelerated to twice its tempo. There was a great lurch as the ship bolted forwards. I fell against the rail of the stairs. The increase in speed was astounding.

The drum boomed louder and louder, faster and faster. The messenger pushed past me again, heading up to the deck. I grabbed the sleeve of his tunic. 'Pirates!' he said, with a theatrical Hit in his voice. 'Two ships slipped out of a hidden cove as we passed. They're after us now.' His face was grim, but as he tore himself from my grip, astonishingly enough, I thought I saw him laughing.

I began to follow him, then stopped, arrested by the sudden spectacle all around me. The drum boomed faster. The rowers groaned and followed the tempo. The whipmaster swaggered up the aisle. He cracked his whip in the air, loosening his arm. The rowers cringed.

The beat grew faster. The rowers at the outer edges of the ship were able to stay in their seats, but those along the aisle were abruptly driven to their toes by the heightened motion of the oars, scrambling to keep up, stretching their arms high in the auto keep the gyrating oars under control. Manacled to the wood, they had no choice.