The old knight shook his head. But he picked up an ornate helmet with cheek plates that still moved on their hinges and put it on his head. It sat on his wool cap.

‘Good vision,’ he said. ‘How old is this?’

Swan shrugged again. But he was happy to have the knight’s interest, and he stood up, cracking his head on the deck beams and subsiding while the knight laughed.

‘Some day, I’ll make a sailor of you,’ he said.

‘I think it’s from before Christ. Before Rome. There was a great battle at Marathon that set Athens on her road to greatness – at least, that’s what Herodotus says. I went there. I bought the helmet from the priest.’

‘I like it,’ said the knight. ‘The time of Troy!’

Swan smiled. ‘Near enough,’ he said. He’d learned that, like convincing adults of his innocence, teaching people about the complications of history was largely a waste of his time.

Drappierro poked his head in through the door. ‘Gentlemen,’ he said in his deadpan voice, and then he saw the helmet. ‘But it is magnificent!’ he exclaimed.

Fra Tommaso handed it to him silently, and the man all but glowed. He ran his fingers over the fine web of embossed olive leaves and lions at the brow. ‘Please allow me to buy this from you,’ Drappierro said. Then he looked at the table. His fingers darted out and grabbed the matching seal rings.

‘Where did you find these?’ he asked.

Swan sat back comfortably. ‘I spent three days searching for them, messire.’

Drappierro looked at him, eyes narrowed. ‘Where?’ he asked.

Swan had played cards long enough to keep his face blank. ‘Near Athens,’ he said.

‘I’ll take them – and the helmet. What’s this?’ he said, putting a hand on the phallus and then pulling it away as if burned. ‘Obscene! And the rest of this is junk.’

He began to admire the seals. Then he dropped them in his purse.

Swan thought, And they call me a thief! ‘Messire needs to purchase them if he desires them so strongly.’

Drappierro flicked his fingers. ‘Talk to my staff. I do not deal in domestic matters.’

Swan leaned forward, slapped a hand on the table, and with the ease of long practice, slipped Drappierro’s purse off its hook while the man was watching his other hand. He withdrew his rings, took his helmet off the table, and bowed.

‘When you have negotiated a price and paid it, you may have these items, messire, and not until then. I collect for the Pope and several cardinals and the – ’ he hoped his hesitation didn’t show – ‘the Duke of Milan.’

Drappierro shot to his feet and fetched his head a staggering blow against the deck beams. He fell, almost unconscious.

Swan took the moment to sweep the rest of his acquisitions into a bag. He was tempted to empty the Genoese man’s purse, but he managed to resist. He tossed it on the table with a healthy clink and went on deck.

The second leg of their voyage was far more comfortable than the first, mostly because Peter had arranged for deck space among the Burgundian archers, and Swan slept both warm and well between Antoine and Peter. Antoine was as welcome with the archers as Peter – even more so when he made them bread in a hastily rigged clay oven on an open beach not far from where the Persian fleet failed to defeat the Greek fleet at Artemesium. The Genoese ambassador had a stop to make on Naxos, and Swan again visited the market and bought coins and a dagger.

A day out of Naxos, he was playing chess with the captain on the quarterdeck. The day was fine, and it seemed possible that spring was not so very far away. The Genoese ambassador came on deck, climbed the ladder to the quarterdeck as if he owned it, and stood watching the sea. He leaned on the rail and watched the game for a dozen moves.

‘I do want to buy those pieces,’ he said without preamble. ‘Cyriaco collected for me. He never charged me. I assumed you were working for him.’ The man’s voice was mild. ‘I apologise for my apparent theft.’

Swan shot to his feet and swept his best bow. ‘I knew that a gentleman of your distinction would be under some misapprehension,’ he said.

‘How much for the helmet and the rings?’ Drappierro asked. Then, his expression slipping, he said, ‘You haven’t already sold them?’

Swan wanted to laugh aloud. How did this man rise to greatness in Genoa? he asked himself. He wears his heart on his face! He rubbed his chin. ‘I’ll sell you both rings and the helmet for two hundred ducats, messire.’

Drappierro nodded. ‘Done. See my chamberlain. See? I am not so unreasonable. When you have been paid, kindly bring them to me. Are we satisfied?’

Swan nodded. ‘Completely so, messire.’ He tried not to roll his eyes.

Drappierro’s chamberlain was a Phokaian Greek called Katzou. He shrugged at the news and opened a small chest and emptied it into Swan’s hat. He made no complaint, checked no document and asked for no validation, and Swan briefly considered a life of crime, but reminded himself that he would be trapped aboard the galley with his victims.

He carried the antiquities to the main cabin, knocked and took them to Drappierro, who sat as he always did at the main table as if he, and not Fra Tommaso, was the captain of the vessel.

‘Ah!’ he said, looking up. His eyes held the kind of lust that Swan associated with old men and much younger women. He snatched the rings from Swan’s hand, looked at them for three deep breaths, and then took the helmet.

Swan turned to go. At the rate of profit, a few more finds sold to Messire Drappierro would allow him to settle comfortably in Ancona and make babies with Violetta. He didn’t need the man to be polite – merely to pay.

‘Wait – Messire Suani.’ The Genoese ambassador raised his hand. ‘I am an abrupt man – I know it. But I see you have taste and some training – hence your friendship with Cyriaco. So – you saw the knight of the order at Monemvasia?’

Drappierro’s abrupt conversational direction changes left Swan gasping like a fish. But he did his best, recovered and bowed.

‘Your Excellency no doubt refers to Fra Domenico?’ he asked.

Drappierro waved. ‘That sounds right. A notorious pirate, albeit one who tends to favour my city.’

Swan nodded carefully.

‘Young man, did you happen to note what the knight wore on his finger?’ asked Drappierro.

Swan pursed his lips and decided on honesty. ‘A ring. Very early – possibly Hellenistic. The gem is a diamond.’

Drappierro looked at him. It was the first time they had met eye to eye – Drappierro’s gaze burned like the look of a religious fanatic at devotions. ‘A diamond, you say?’ he said. ‘Why do you think so?’

Swan eased himself into the cushioned seats against the stern windows. The winter sun reflected off the sea and on to the gleaming white ceiling of the cabin. The heavy deck beams were painted black and red in alternating succession, and the effect with the sun-dapple was stark and beautiful.

Drappierro hadn’t invited him to sit, but Swan was not interested in standing like a servant for this man.

‘I’ve held it in my hand,’ Swan said.

Drappierro leaned forward. ‘You have? Tell me of it in detail.’

Swan smiled. ‘First, it is called “The Ring of the Conqueror”,’ he said. ‘It is Alexander’s signet ring.’

Drappierro became so red in the face that Swan was afraid the man was going to have a seizure. ‘Messire? Do you need water?’

Drappierro leaned back. ‘I have heard of this thing. How do you know it is the real ring?’

Swan shrugged. ‘I do not know. But Fra Domenico believes it is, as did the Turkish corsair from whom he took it.’

‘By the saints – he had it from Khaireddin,’ Drappierro said. ‘It is the ring.’ His slightly mad eyes met Swan’s. ‘What’s carved in the jewel?’

‘Herakles,’ Swan said, in Greek. ‘His head, anyway!’

Drappierro sighed. ‘Why didn’t I stop and look at it? Listen, Messire Suani. The Grand Turk wants that ring. Very badly. If I could give it to him, I could get any treaty I wanted. Perhaps even reclaim some of my losses from the infidel.’