Robert was entranced.

On the second morning they made their way to Sihtric's small town house. Robert's heart quickened when Moraima joined them.

Sihtric served them watered wine, and announced that later in the day he would introduce Orm to his sponsor, one Ahmed Ibn Tufayl, a vizier of the emir of the taifa which now owned Cordoba. 'When he heard you were coming, Orm, the vizier demanded I bring you to him. The caliphs always saw off the Vikings; this wasn't Alfred's England, weak, backward and divided, and there are few Vikings here. So you're an object of curiosity!'

'I hope I don't disappoint,' Orm growled ungraciously. In the bright Spanish sunlight he was massive, heavy, somehow dark, Robert thought. He wasn't comfortable here. And his head probably hurt from the monkish wine he and Sihtric had consumed the night before. Orm said to Robert, 'Don't you notice anything different about me today?'

'By God's eyes. You cut your hair.'

He stroked his chin. 'Look, a good shave too. And I had a bath.'

Robert was genuinely shocked. 'You didn't.'

'I went to one of those bathhouses the Moors have. Quite pleasant it was, if you can put up with smelling like an East Roman whore.'

Ibn Hafsun smiled. 'You have to make yourself presentable to meet a Muslim ruler. Clean clothes, a wash. The envoys of the Christian kings, even of the Pope, have always known this. Of course Christians aren't quite as in awe of the Moors as they were in my father's day.'

Moraima, serving more wine, passed Robert. 'I'm glad you haven't bathed. I quite like the way Christians smell.' And with a fleeting, luring smile, she turned away.

Sihtric lectured them about Cordoba's magnificence. 'At its peak, only a generation ago, it was the greatest city in the west. Why, its population even matched Constantinople. Five hundred mosques. Three hundred bathhouses. Fifty hospitals. Do you even know what a "hospital" is, young Robert?

'And the greatest library in all the world, it is said, flourished here in Cordoba, under the caliphs. It all started when the East Roman emperor sent the caliph a copy of a pharmacology text by Dioscorides – have you heard of him? It was like dropping a bit of hot iron into a pan of water. Scholarship boiled in al-Andalus…'

The caliphs, rich and at peace, embraced learning as an emblem of power and sophistication. And they were much better placed to do so than western Christendom, for they had access to the surviving works of antiquity. Employing legions of copyists and translators, the Moorish scholars merged Greek and Roman learning with what their cousins in Damascus and Baghdad had acquired from the Persians, and they built on what they learned. The result was a flowering in astronomy and physics, medicine and philosophy.

Sihtric said, 'The library itself grew to four hundred thousand books. The catalogue alone ran to forty-four volumes! This was at a time when the kings of England were entirely illiterate. But when the caliphate fell the library was broken up. How I wish I had been born a generation earlier. But there are still books milling around the city, as if released into the wild. It is my skill at tracking the books down as much as my learning that makes me so useful to Ibn Tufayl, I think…'

Sihtric was a man of contradictions. For all his admiration of Cordoba's Moorish achievements, he was keen to play up its deeper Roman origins.

'All of western Europe is the same. All of us dwelling in the vast ruins of the empire, four centuries after some German brute pushed aside the last boy-emperor from his throne. Did you know that the philosopher Seneca came from this very town? And the Emperor Hadrian himself, who made his mark on Britain as you know very well, Orm, came from the Spanish city the Roman called Italica, which is now the capital of our local taifa, Ishbiliya, or Seville…'

As he droned on, Moraima, without warning, grabbed Robert's hand, held her finger to her lips and hauled him out of the room. 'Come on. By the time they notice we've gone we'll be far away.'

Robert was thrilled to be off on an illicit adventure with Moraima – to be alone with her at last, with no fathers or lusty camel-drivers in the way. But a lingering sense of duty prompted him to say, 'We have to see this vizier-'

'I'll get you to the palace in time. I thought you were a warrior – you' re very timid. Come on.'

So they set off, holding hands, giggling and half-running like children.

She led him to a market, crowded and noisy, where stalls were piled high with tiles and bowls, with fine velvets and felts and silks. Moraima said that Cordoban shoes and carpets and paper were famous throughout the Muslim world. There were exotic imports to be found too: the fur of walrus and polar bears from Scandinavia, carved ivory and gold trinkets from Africa, silk, spices and jewellery from the east, even fine wool from England. One stall had a pile of fruit that Moraima had to name for him, save for the oranges: lemons, limes, bananas, pomegranates, watermelons, artichokes. Not even the Norman kings, Robert imagined, ate such exotic stuff as this.

Moraima said, 'They say Cordoba is more like Africa than Europe. That Paris is not like this, or London.'

'Africa starts at the Pyrenees,' Robert said, echoing his father.

'I've never travelled beyond the Pyrenees. I'd love to see London. Or York.'

'I've seen those places, and more.'

'You're lucky.'

He shrugged. 'My mother died when I was small. I go where my father goes. He's a soldier. Somebody's always rebelling, and he goes to sort it out.'

'And London-'

'Big. Dirty. Crowded. A cathedral like a big black pile. The Normans are building an immense fort in the corner of the old Roman walls. And York is a midden. It never recovered from the Normans' harrying twenty years ago.'

"'Harrying"? What does that mean?'

'Ask my father. He was there.'

But that wounded country seemed far from this light-filled city, very far and somehow unreal. 'You know, you aren't much like your father,' he said.

'How so?'

'You seem full of…' He sought the right word. 'Joy. Your father doesn't seem joyful at all.'

Moraima shrugged. 'He admires the city, the Moors' accomplishments. He relishes the learning. But he despises it at the same time. I think he has to despise it, for it is not Christian.'

'And yet he stays here,' said Robert. 'Why? For you?'

'Yes, for me.' But she said this without emotion. 'And he has his projects. Something to do with the library, the books. History.'

'All for the vizier?'

'Paid for by the vizier, yes, but not all for him.'

'What projects, then?'

'He doesn't tell me.' That seemed to embarrass her, and she said, 'What about your father? Why is he here?'

Robert sighed. 'Something to do with your father, and what he's up to. Though how a bit of book-reading in faraway Spain can affect him I don't know.' He looked at her. 'Moraima – we keep talking about them.'

She said coyly, 'So what do you want to talk about?'

He dared to say, 'We could start with the way your eyes match the blue of the sky.'

She gasped, and he saw he'd pleased her. 'You'd like our poetry,' she said, recovering quickly. 'It's full of lines like that. Eyes like stars and breasts like billowing clouds-'

'Maybe I should read you some,' he said.

But she wasn't to be snared so easily. 'Well, how about the colour of the vizier's eyes when we turn up at his palace late? Come on!' And she turned and ran through the market crowds.

Utterly lost in the heart of the city, he had no choice but to follow.