‘Hmm? Oh, yes. I’m sorry. We don’t have such magnificent books where I come from. These are really very special. The pages . . .?’ He angled the book to the light to see them edge on.

‘Vellum, mostly. Some are cloth treated with fine clay.’

‘Where do books like this get made? There must be a king’s ransom in this box.’

Bin Haji smiled nervously. ‘I . . . yes. They are very precious. Most are out of the scriptoriums of Misr.’

‘I’ll have to go there.’ Benzamir slipped onto one of the divans, still holding the second book. ‘The stars. More specifically, stars that move.’

‘The stars are fixed: they do not change. If there were something new in the sky, it would not be a star. Perhaps you mean one of the planets.’ Bin Haji frowned. ‘You do have some knowledge of the heavens?’

‘Yes,’ said Benzamir enthusiastically, ‘I do. I need to know if you or any of your congregation have seen a bright light, or maybe more than one, falling from the sky to touch the ground. Have you?’

‘No. Nothing out of the ordinary. There are the usual lights in their seasons, the so-called shooting stars, but nothing like you describe. Are you searching for a thunder-stone?’

Benzamir had to think. ‘A meteor. It would look like one, wouldn’t it? If one had fallen, where would I go to find out about it? Who would gather news of that sort?’

‘If you dare, the emperor of Kenya’s court. His spies are everywhere.’

‘Are they? Why?’

‘Because,’ said Bin Haji, ‘he has the vanity to want to know all things. You really are from far away not to have heard of Kenyan spies.’

Benzamir opened the book on his lap. It was an atlas. He gasped with delight. The pictures were just what he’d expected. ‘This is pre . . . pre . . . what do you say here?’

‘Before the world turned.’

The pages were thick and crisp, faded with age. Benzamir could see errors wherever he looked: bays lost, headlands flattened, mountains moved, rivers erased. But the gross features were all intact, and even some of the old names persisted. North was still north, though much of the writing was upside-down. He moved his finger along the coast from where he was to Misr El Mahrosa. Except that the city was far inland and there was El Iskandariya on the edge of the blue sea.

He turned more pages. Each one was a painstakingly copied work of art. The maps the transcribers had recent knowledge of were annotated heavily. Those of lost lands were sparse, and often wrong.

‘You’re a rich man. I thought the sheikh was blessed, but you . . . you’ve the wealth of knowledge here, and it’ll keep you and your children’s children in high regard.’

‘You would like to think so. I have no wife yet.’

‘Then you have to find one. These are too precious to pass into the hands of someone who doesn’t appreciate them. Or worse,’ said Benzamir, ‘Ibn Alam.’

‘We do not speak ill of the heir of Alam in this house,’ chided Bin Haji. But he seemed neither outraged nor scared by Benzamir’s criticism. ‘There is time enough for marriage later. I am not so old. If you like my maps, perhaps you will also enjoy this.’

He bent down and reached under a divan. As he lifted the cover, he revealed a row of boxes, all different shapes and colours. He picked one, and slid it out. He beckoned Benzamir over and gave the brass key a half-turn.

Benzamir knelt on the floor and watched as the lid of the box was lifted clear. What was inside was delicate in the way carved ice was delicate. There was a ring of metal, engraved with script and pierced with tiny holes. Then, balanced on fine wire above five concentric rings, small coloured balls. Around the third ball there was an additional ring, with its own tiny ivory sphere.

‘It’s an orrery.’

He touched the polished brass orb that represented the sun, and watched the way his fingerprint evaporated in the heat.

‘It used to be clockwork. My father had it converted to a hand crank. The dust causes havoc with the mechanism.’

‘Is it accurate? I mean, it has to be more than a toy.’

Bin Haji reached inside the box and retrieved the little handle. There was a hole in the side which fitted the square end perfectly. ‘The Earth goes around the Sun once, and the Moon goes around the Earth thirteen times. The Moon keeps its face to us, while we turn and turn, once a day. The other planets do not spin, but make their circles about the centre. Watch.’

He worked the orrery, and the planets danced for Benzamir. Each individual ring was inscribed with its Arabic name: Zuhra, Ard, Quamar, Merrikh, Mushtarie, Zuhal.

‘The planets fall out of alignment after four or five years, and need to be reset by making your own observations. It is a toy, though a very beautiful one.’

‘Don’t you use it to teach with?’ asked Benzamir. ‘Such a thing is worth any amount of explanation.’

‘The people here – well, they are not scholars. They fish. They grow crops. They keep sheep and goats and camels and cows. To know when Venus rises, or when Saturn and Jupiter are in conjunction? It might be interesting, but it is not necessary.’ Bin Haji stopped winding, and sat back on his haunches. ‘They are not ignorant, but their priorities direct their learning.’

‘Yes, of course. My people value learning highly. We’re always looking for the opportunity to learn something new.’ Benzamir peered into the heart of the machine. He could see the toothed cogs and wheels. Each one would have to have been cut with great accuracy by hand. ‘Where was this made?’

‘In the west. Misr El Mahrosa perhaps, or in lost Iskandariya. Long before I was born.’

‘Could it be made now? I mean, are there craftsmen who could replicate this? There’s so much engineering and astronomy that’s gone into this: differential gearing, the understanding of elliptical orbits, even the rings are angled slightly from the ecliptic.’

‘I do not know. You would have to go and ask,’ said the imam quietly.

Benzamir looked up, troubled by Bin Haji’s sudden change of tone. ‘Have I said something out of turn?’

‘You use words that I do not understand, yet you use them with complete familiarity. Again I ask you, where are you from?’

‘From here, originally. My ancestors lived in the Atlas mountains.’

‘How many generations ago did your people leave? There are no clans up there you could belong to. You are too different.’

‘We left seven hundred years ago, before the world turned. We left in ships that landed on strange shores, beyond . . . beyond wherever you think of as far away. Now it’s my privilege to return. Of all my people, I’m the first to make the long journey back.’ Benzamir smiled in what he hoped was a friendly fashion. ‘It’s changed less than I thought.’

Bin Haji looked sceptically at him. ‘Aside from north being south and south being north.’

‘I’m a son of the desert, as the sheikh says. The stories of my forebears live in me. I’m not so different after all.’

‘You would do well to guard your tongue. Talk of “differential gearing” is likely to lose you friends and risk you being mistaken for a sorcerer.’

‘That would be bad, I take it.’

‘You would be stoned. Or drowned.’

‘Ah. Thanks for the warning.’ Benzamir stood. ‘I don’t want to outstay my welcome. You have evening prayers to attend to.’

‘You are a confusing man, Benzamir Mahmood. I would have you down as a Kenyan spy were it not clear that you had never heard of them before.’ The imam started to close up the orrery, and Benzamir put the books carefully back in the trunk.

‘Salam alaykum, Imam.’

They exchanged kisses on their cheeks. ‘Why do you search for stars that fall from the sky?’ asked the imam.

‘Because it’s a sign that my enemies are near. If you hear of such things, send word at once.’

‘Where should I tell the messenger to go?’

‘Everywhere. Sooner or later, he’ll find me. After all, that’s how I’m having to search.’