Giannis saw what he wanted and went to the bishop.

Swan got his hands on the armet. The tight-wrapped cloth inside the helmet looked intact.

He shuffled towards the market.

Giannis got the bishop on to his shoulder and followed him.

Cesare joined the Greek and took the man’s legs, and they ran in a sort of sideways shuffle towards the fountain.

North along the avenue, Swan could see a man in a plumed turban on a fine bay horse. He was at the head of a squadron of Turks – perhaps a hundred. He had a horse-tail riding whip in his hand, and he used it to gesture – at them.

Swan placed his helmet carefully on the ground, picked up the Spaniard’s abandoned bow, fitted an arrow from a Turk’s nearby quiver, and took a deep breath.

‘Swan!’ roared Alessandro.

They had the bishop at the edge of the fountain.

He raised the bow. The range was extreme – two hundred paces, at least.

He drew the nock of the arrow all the way to his own ear, as his uncles had taught him. It felt odd with the small Turkish bow, but it seemed to pull very much the way the bows of his youth pulled. Heavy. But beautifully balanced.

He raised the sharp, barbed point of the arrow twelve fingers above Omar Reis’s head. He compensated for the breeze, let out a little breath, and loosed, his hand flying from the string as in a dramatic plucking of a harp.

He ignored the shouts of his companions and watched the fall of his shot, because it felt right. An archer knows.

The arrow rose high over the streets of the ancient city, and then, like one of Idris’s falcons, it fell.

The Wolf of Thrace and his horse fell silently, two hundred paces away. The horse kicked, and dust flew, and Swan could see no more. He turned, scooped up the helmet, and ran.

‘I got him!’ he whooped like a boy when he caught Alessandro.

‘Got who?’ asked the Venetian.

‘I put an arrow in Omar Reis!’ He laughed.

Alessandro looked at him in disgust. ‘If you have done such a foolish thing, they will hunt us to the ends of the earth,’ he said wearily. ‘Now lead us through your sewers.’

There was no further pursuit.

In an hour, the exhausted and bedraggled survivors were in the Venetian quarter. Swan was pissing blood; the Spaniard had an arrow in his left thigh that the Venetian quarter barber-surgeon refused to touch, and Alessandro sent him on his way. A sailor was dead; another of the marines badly wounded with an arrow in the shoulder, and all of the men-at-arms were virtually unable to move from exhaustion.

The two Venetian galleys were on their way, halfway across the Golden Horn. The sun was setting. But north and west of the Venetian galleys, half a dozen Turkish galleys were crossing their lateen yards and making ready for sea.

The bishop had been pinked by two arrows, and was badly bruised by rocks and clods of earth, and despite that, he was everywhere, hobbling on a makeshift crutch, full of spirit – almost cheerful.

Alessandro watched him.

‘Not what I expected,’ Swan said carefully. Alessandro seemed to blame him for the whole incident.

But the Venetian shrugged. ‘He has surprised himself,’ said the Italian. ‘He is braver than he thought, and a better man. It has made him . . . happy. I have seen this before.’ He managed a rueful smile. ‘Perhaps never such a volte-face as this, but still . . .’

Cesare was downing a cup of wine. ‘Christ, what if we had to like him?’

The Venetian bailli entered the yard of the inn and began to shout at the bishop.

Alessandro still had his armour on. He waved at the rest of the party. ‘Get your kit to the wharf. Now. Immediately. The bailli is threatening to hand us over to the Turks.’

Swan was on his way to his room when he realised that the small boy standing at the open front door of the inn was familiar. The boy brightened when he saw Swan.

‘King David is looking for you. At the gate!’ he said. And off he ran, in the way of small boys.

Swan thought about it.

Isaac might have something useful to say. He would certainly have a packet of his letters for Venice.

Or he might have a party of Turks – or even a dozen mercenaries, to take Swan alive, and hand him to Omar Reis, if he lived.

I don’t have to do this, Swan thought.

So he went. He was in armour, with his sword at his side. His buckler was lost.

There was no janissary at the gate. Instead, there was Isaac.

‘How did you escape?’ Isaac asked as soon as Swan appeared.

‘I have some tricks,’ Swan said wearily. ‘I shot Omar Reis.’

‘You killed Omar Reis’s horse,’ Isaac said.

Swan laughed. Perhaps it was the fatigue, or the heat, or the wine, but he laughed and laughed, and he couldn’t stop, like a small child. Isaac shook his head.

‘The Turks will be here in a few minutes, to demand you be handed over,’ he said. He pointed across the square, where Yellow Face was obvious by an ancient archway. ‘I have to know. How – how exactly – did you get out of Bessarion’s house? I had watchers, and you eluded them.’

Swan rubbed his beard. ‘Trade secret, which I will sell you. Can you delay the Turks by an hour?’

Isaac gestured at himself with both hands. ‘I? A mere Jew?’ He shrugged.

Swan waited.

Isaac rocked his head back and forth. ‘Ah. Perhaps I could at that.’ He narrowed his eyes. ‘I think they want you to get away. I think they have decided to use you as an . . . incident. If they catch you – that might be inconvenient for them as well.’ He handed Swan a heavy packet. ‘My letters for Venice. And my cousin Simon’s, as well. He did not, as it turned out, sell you to the Turks.’ The Jewish merchant nodded. ‘There is a letter in that packet addressed to you. Lord Idris brought it to my brother. In person.’

‘Good Christ,’ Swan said.

‘Omar Reis will want you dead, even if his master Mehmet has decided to let you go,’ Isaac said. ‘Nonetheless, I can purchase you an hour of time.’

Swan reached into the leather bag he wore at his shoulder, and took out his tablet of paper, and tore off his map of the sewers and conduits. He handed it to Simon with a bow – he didn’t have the power in his muscles for a flourish. ‘They don’t all link up,’ he said sadly. ‘I thought they would. But you can pass from one to another without being noticed, if your hunters don’t know where to look.’

Isaac was looking at the map. ‘These aren’t streets—’ he said slowly.

‘Sewers. The ancient cisterns. That’s my map.’ Swan leaned back against the gate to the Venetian quarter.

Isaac laughed. ‘You know the sewers?’ he asked. He shook his head. ‘Hug my cousin Balthazar for me. Pass that packet on, and he will see you rewarded, I promise. You have been . . . most entertaining, Messire Swan.’

Swan embraced the man, who seemed surprised to be embraced – but they kissed each other’s cheeks, and Isaac chuckled. ‘Go with God, Frank,’ he said.

‘Thanks!’ Swan said, and ran back through the gate.

‘Wait!’ Isaac called. ‘Where did Bessarion’s library go? And what if I find you more books?’

Swan waved.

They boarded Nike in minutes – the men in their armour, the embassy boarding with greatly reduced baggage. Bags went straight to the hold under the rowers’ feet, and Swan took a moment to grab an old, open-faced bascinet from the Venetian guardhouse and put it on his head.

Alessandro came and stood by him at the edge of the command deck. ‘Where – exactly – are we picking up this boat?’ he asked.

Swan pointed a mile down the European shore of the Horn. ‘Right at the point.’

Ser Marco grunted. ‘Where the currents are the worst. Nonetheless – any Venetian knows those waters. That is where Dandalo stormed the city.’

Claudio, the surgeon, was already at work on the Spaniard before they were under way. And north of them, three Turkish galleys left their docks and started down the Horn towards them in the failing light.