Khatun Bengül leaned in from Swan’s other side. ‘He uses me to protect him from Father,’ she said.

Swan looked at her. When he breathed in, he tasted her scent over the smell of flowers and grass and horse.

‘She uses me to protect her from Father, too,’ Idris said.

‘I am a nice girl,’ Khatun Bengül protested. ‘I just like to ride.’ She shrugged. ‘And I can do anything a man can do. Better. Men are all fools.’ She tossed her head.

Behind them, all of Idris’s friends were watching her.

Swan took a deep, steadying breath. ‘Yes,’ he admitted. ‘Every one of us.’

‘Sufia will be in our stables – but available for you at any hour,’ Idris said. They rode past the great aqueduct, through the forum of Constantine, and past the north end of the Hippodrome to the great houses beyond Hagia Sophia.

Swan breathed a sigh of relief when his horse was not stabled in the great cathedral. Sacrilege had its limits.

They rode into the palace quarter and dismounted in the courtyard of a fine square of buildings. Workmen were facing the front of the stables with beautiful fired tiles in a rich blue with the trailing cursive of Persian script. Less than a hundred paces away, a tall minaret was being built on to a low Byzantine church.

Swan handed his horse to a pair of slaves. He put a hand familiarly on Idris’s arm. ‘You have your friends,’ he said. ‘I should go.’

Idris bowed. ‘You are a good guest. Will you come riding again?’

Swan smiled. ‘My lord, the bishop will probably give birth to a cow when he hears that I spent the day with infidels.’

Idris laughed. ‘Tell him my father will have his guts ripped out of his fat stomach if he stops you.’

Idris meant these words as a joke, but they chilled Swan.

Idris leaned closer. ‘Listen – you know this is all a sham? Don’t you? In the spring, my father will lead an army into the Morea and we will take everything Venice has. It’s not even a secret.’

Swan struggled to maintain his composure.

‘Don’t let it come between us,’ Idris said. He smiled. ‘I treasure you. Come ride with me again tomorrow.’

Swan bowed low. ‘I’ll try.’

He was pleased when several of Idris’s friends offered him casual salutes. As if he was a person. Others remained studiously aloof.

He turned and crossed the courtyard. But Auntie blocked his route with her pony. She smiled at him.

He smiled back at her. It was his habit to smile at any pretty woman who smiled at him.

‘She’d like to have you in her bed,’ Khatun Bengül said. ‘But she doesn’t know how to ask.’

Swan, seldom at a loss for words, had none for this situation.

Khatun Bengül laughed. ‘You flush like a girl,’ she said. ‘Will you come and fly a bird with us another time?’

Swan bowed. ‘Perhaps, if my duties allow. The company was . . . divine.’

‘Divine?’ Khatun Bengül tittered. ‘Now, from one of these young men, that would be blasphemy.’

Swan wasn’t sure whether he’d scored or not. So he smiled, bowed again, and walked out the gate.

Despite feeling utterly smitten, he walked straight into the alley that separated Omar Reis’s palazzo from the next magnificent structure and walked south. He was disappointed that his sense of direction had failed him – he didn’t emerge into the street on which Bessarion’s house was situated. He looked behind him, and at the cross-street. He didn’t see any sign of Yellow Face or Tall Man, as he had christened them.

So he followed the next alley south.

There was Bessarion’s house. It rose three stories above the street, and was surrounded by a high wall. There were outbuildings – a stable, a slave or servant quarters, and perhaps a workshop.

He walked all the way around the compound. The gates were locked. There were beggars living in the arch of the front gate.

He paused.

‘Effendi!’ said one woman. ‘Do not harm us!’

‘Do you speak Greek?’ he asked in that language.

All of their faces brightened. There were four of them – filthy, but well enough fed, he imagined.

‘Whose house is this?’ he asked.

The old woman shrugged. ‘Some dead Frank,’ she said.

‘No infidel lives here?’ he asked.

They looked fearful.

‘Has a Turk taken the house?’ he insisted. He was dressed as a Turk – the word infidel could go either way.

‘None yet in this street,’ the old woman said.

She was obviously concealing something.

He dug into his kaftan and produced a silver byzant of some value or other – the Turks hadn’t produced a coinage yet, and Byzantine coins were notoriously debased. But it must have some value.

He tossed it to the old woman. ‘How can I get in?’ he asked.

She looked at the coin.

‘I can come back with janissaries,’ he said.

She looked terrified. ‘Effendi – we live in this gate.’

‘You may continue, for all I care,’ he said.

‘We know how to open the gate,’ she said.

He produced another coin.

But it was all taking too long. And it was late afternoon, and the Turks were hurrying to the little mosque for prayers, and suddenly the once-empty street was full.

‘Perhaps another day,’ he said, turned on his heel, and walked away.

Something felt wrong. He didn’t know what, but something felt wrong.

He walked all the way to the Venetian quarter. He was afraid that he’d be stopped because of his Turkish dress, but no one stopped him. In fact, a janissary in the street saluted him.

It was almost dark by the time he reached the Venetian Quarter.

He sat in a tavern with Giannis, Alessandro and Cesare, and related the events of the day. He left Khatun Bengül out of it.

When he spoke of the spring campaign against Venice, Alessandro swore.

‘I heard the same from some of the Jews,’ Swan said.

Alessandro shook his head. ‘Foscari is so focused on the war in Italy, he’s forgotten the Turks and how perfidious they are.’

Giannis agreed.

Swan took a drink of wine. ‘They seem . . . fairly straightforward to me.’ He wanted to say ‘compared to Italians’ but he knew the audience was wrong.

Alessandro sighed. ‘If only the bishop were not a complete fool,’ he said. ‘I feel I cannot share this with him.’

Giannis scratched at his hairline. ‘I could perhaps rent a boat. Go to Galata, and inform Ser Marco.’ He shrugged. ‘But I couldn’t come back.’

‘Surely they know?’ asked Swan.

‘Let me speak on behalf of my beloved Signoria,’ Alessandro said. ‘We are a nation of sea merchants, most of whom would sell their mothers as whores to make a profit. Money, and the search for money, has its own blindness. And its own pitiable lack of scruple. If a Venetian thinks he can make a profit . . .’ He shook his head. ‘Perhaps some know, but conceal the knowledge. Perhaps others close their minds to the news.’ He shrugged. ‘Perhaps it is inconvenient,’ he said.

Giannis spat carefully. ‘In the Morea, we say that the difference between a Turk and a Venetian is that at least the Turk believes in something,’ he said.

‘Blessed Virgin,’ Swan said.

‘You must go,’ Alessandro said. ‘I cannot – my absence would be obvious. Swan would be missed by his Turkish friends, and so far, he’s the only one of us to see the cardinal’s house.’

Giannis finished his wine. ‘I’ll be in Galata before the sun rises,’ he said.

‘It’s after curfew!’ Alessandro said.

‘Give me your Turkish clothes,’ Giannis said.

Swan thought for a moment. ‘I love that kaftan,’ he said, but Giannis, who hated everything Turkish, assumed he was kidding.

At nightfall, the janissary at the gate sent for Swan. When he presented himself, the janissary bowed, and handed him an ornate parchment. A firman. A pass, signed in Persian script, for Thomas Swan, Prince of Britain.

At daybreak, an African servant handed a note into the Venetian quarter asking Swan to come for a ride in the countryside. The note was unsigned. On the back, in neat Italian, it said, ‘Come in secret.’ Swan smiled to himself.