'That would seem a crime,' Ibn Hafsun said. 'It is a unique artefact… Can I suggest a compromise? Let me take it. I will put it in safekeeping for you – or for your children, perhaps.'

'Safekeeping?' Moraima asked. 'Where?'

Ibn Hafsun thought it over, and had an inspiration. 'Right here. I'll put it in a box, and have it interred, under our feet. One day a great mosque will rise up here on this very spot. Surely it will be undisturbed there. And if you or your descendants ever want to retrieve it – well, you know where to look.'

'Are you an honest man, Ibn Hafsun?' Robert asked. 'You won't take it and exploit it for yourself?'

'Not I,' said Ibn Hafsun. 'I don't have the imagination for such things – or the stomach. After all I am caught between two worlds; who would I attack, my Muslim brothers or my Christian cousins? You can trust me, Robert Egilsson. I hope you know that of me by now.'

Robert and Moraima eyed each other. 'Agreed,' said Robert.

She nodded.

'And for you two,' Ibn Hafsun said sadly. 'Is there no hope?'

'No hope,' Robert said.

Moraima asked coldly, 'What of the baby?'

Robert shrugged. 'Have it born. Have it scooped out of you by your clever Islamic doctors. I don't care. It is your responsibility, only my shame.' And he turned to walk away.

'A shame that will haunt you, Robert,' she called after him. 'Haunt you!'

He kept walking, faster through the narrow streets, until he could no longer hear her voice.

As he approached the river he dug into his pack, checking his money.

And he found al-Hafredi's bit of tattooed wrapping skin, and scraps of the fire-damaged Codex, torn off. These fragments had been left behind when he had pulled out the scroll. He picked out the largest bit of the Codex, held it up in the bright Spanish sun, and studied it curiously. The words Incendium Dei had been ripped through, leaving incomplete letters, D, I, V, M. And there was a string of garbled lettering:

Perhaps he should discard these bits of grisly, enigmatic rubbish. But that felt wrong. After all men had died for this – his own father had.

He thrust the scrap back into his pack, with the bit of human skin. He could decide later. Then he walked along the river front, looking for a ship to England.

'On the day he left Seville Robert was only fourteen years old,' Joan said. 'A year younger than you are now, Saladin. He grew to become strong and pious – but a savage warrior, a driven man, it was always said. He took the Cross, and won Jerusalem. And he died on Temple Mount, far from home. This Christian country was his enduring achievement. Since then six generations of his children, six generations of us, have lived and died here. But Robert, that confused boy, has vanished into time, his life transient as a breath…'

Saladin sat with his mother on a blanket spread over the dusty ground of the Mount of Joy. On the hill a goat bleated, and their tethered horses grazed peacefully. The sun was high, the last of the morning's cloud was shredded, and a sharav, a desert wind, hot and dry and scented like spice, stretched the skin of Saladin's face tight as a drum.

All of Jerusalem was spread out before him, the domes of its mosques and churches and the swarming of its many bazaars and suqs all crowded within the wreckage of the old walls. Faint voices called the Muslim faithful to prayer, and somewhere the bell of a Christian church tolled. To the east he could see the Dead Sea and the Jordan. To the west the Mediterranean gleamed. It was hard to believe that any of this would ever change, that he himself would ever grow old. And he felt uncomfortable with his mother's talk of a long-dead boy.

'I don't like it when you say things like that,' he said.

'Like what?'

'Like a poet. "Transient as a breath." What does that mean?'

Joan sat wrapped in a loose white robe, with a scarf over her head to deflect the sunlight. While Saladin was dusky she was pale, her eyes blue, and the sun burned her easily. Saladin had heard it said that he looked as if he belonged here, but she did not, though the line of her ancestors since Robert the Wolf spanned a century and a half.

She was only thirty, he reminded himself. Her husband, his father, had died young, and she had worn herself out raising Saladin, and defending the family's wealth and position in Jerusalem. He knew all that. But her earnestness made him impatient. He felt like a slab of muscle, restless and confined.

She sighed. 'I'm trying to waken your soul, Saladin. Trying to give you a sense of the history in which we're all embedded.'

'Who cares about history? You can't change history, you're stuck with it. The future is all that matters.'

'Dear Saladin. You're just like your father, you know. His brain-pan was as hard as iron too. And he cared nothing for history either. But history shapes all our lives. The great currents of time have brought us here, you and I, to this hill over Jerusalem, far from the birthplaces of our ancestors – of Robert.

'And what's more it wasn't until your father died, and I had to take responsibility for his business affairs, that I learned that all our family's fortune is based on history – or rather our family's strange knowledge of it, and of the future. Your father kept that from me. Soon you will need to learn the truth. Saladin understood history, and his place in it, you know,' she said. 'I mean the first Saladin the Saracen, your namesake. That was why he spared the Christian population when he took Jerusalem. It was a gesture which will cast a shadow across centuries.'

Saladin didn't always appreciate bearing the name of a Saracen, even the greatest and most honourable. 'Can we go back to the city now? You know how hot you get.'

'Not just yet. There's something I need to tell you. We are to receive a visitor. From England.'

Saladin was thrilled. To him, England, birthplace of Robert, and of Richard the Lionheart, the greatest Christian warrior of all, was as remote and exotic as the moon. 'Who? A knight, a prince?'

She laughed softly. 'Somebody much more useful. He is a man called Thomas Busshe. He is a monk, a friar in a Franciscan monastery near Colchester. But he also lectures on theology and philosophy in Oxford.'

Saladin's disappointment was crushing. 'A monk,' he said with disgust. 'A scholar. I don't even know where Colchester is.'

'It's an old city, north of London.'

But Saladin had no clear idea where London was either. 'So why is this fat old scholar hauling his backside from one end of the world to the other?'

She laughed again. 'Actually he has two purposes. He wants to speak of the Mongols, and our family's business. And he means to deliver me a letter. It was sent to his monastery, but it is intended for us. It comes from Cordoba.'

He frowned, thinking through his mish-mash geography. 'Cordoba? The city of the Moors in Spain?'

'Who would write to us from Cordoba, do you imagine?'

'Family? A Christian warrior?'

'No,' she said carefully. 'Quite the opposite. Our correspondents are Moors, Saladin. Muslims. And yet they are cousins. And yet they are descended from Robert the Wolf, just as we are…'