The next day Robert ignored his duty with the camels. He pushed his way up the column so he rode closer to Ibn Hafsun, and spoke to him.

The Spanish peninsula, he learned, was like a vast square, all but cut off from France by a chain of mountains, the Pyrenees. More chains of mountains crossed the interior, running roughly east to west, and in the lowlands between the mountains rivers snaked over the land. Four of the five greatest rivers drained west into the Ocean Sea.

The north-west corner, around Santiago de Compostela, was green and temperate, and many people made a living from the sea. In the south-east was more greenery, and there the Moors ran market gardens, rich with fruit trees. But here they were passing through the heart of the country, a vast extent of arid lowlands cut through by the mountains and rivers. The Christians in their degenerate descendant-tongue of Latin called it meseta. The winters were long and bitterly cold, the summers dry and intense. There were no woods here, and little in the way of grass, only patchy scrub. No small birds sang, Robert noticed, for there was nowhere for them to nest; only buzzards wheeled, and eagles scouted the hills.

‘And the Christians and the Moors?’

Ibn Hafsun said, ‘You must think of Spain as sliced into three: the Moors in the south, Christian kingdoms in the north, and a kind of frontier land between. As the Christians have gradually grown stronger, the frontier has, with the centuries, been pushed southwards. Now that the Castilians have captured Toledo the frontier roughly cuts the peninsula in two, east to west: the north Christian, the south Moorish.’

Robert nodded, picturing it. ‘And one day that frontier will be pushed all the way south, and Spain will be free of Moors once more.’

‘Are you sure? Look around you. Look what the Moors made of this country.’

They happened to be following a river bank. Robert saw that irrigation systems striped the countryside, and along the river itself huge waterwheels turned patiently.

‘All this is Moorish,’ Ibn Hafsun said. ‘There was a high civilisation here, Robert son of Orm. The highest since the Romans. Higher than Christendom.’

‘Not so high,’ Robert said fiercely, ‘that Alfonso’s Christian armies could not drive the Moors out.’

Ibn Hafsun shrugged. ‘Well, that’s inarguable.’

‘Must it be so?’

The soft voice startled Robert. It was Moraima, who had come to ride alongside the two of them. She spoke English, her father’s language, but heavily accented.

Robert said to her, ‘Those are the first words you have spoken to me. And must they be about war?’

‘But it’s all you talk about. You and our fathers.’ Her voice, like her face, was delicate, and yet Robert thought he saw a strength beneath the fragile surface. It only made her more desirable.

‘We weren’t talking about war. Ibn Hafsun was telling me about the country.’

‘Ah,’ said Ibn Hafsun, ‘but you are a warrior of God – a warrior cub at any rate. Tell me that you aren’t dreaming of riding across this land in your mail coat, your sword in your hand, at the side of Rodrigo, El Cid, “The Boss”, the greatest Castilian warrior of all!’

Moraima laughed, a sound like bubbling water. ‘I ask you again, Robert: must it be so?’

Robert said reluctantly, ‘The Pope himself says that if you fight to reclaim Christian lands from infidels, you are fighting for Christ.’

‘Well, the Pope would say that,’ Sihtric called back from his own mount. ‘But the Pope has wider ambitions.’

Across Europe the conflict between Christianity and Islam was already four centuries old. Now the Seljuk Turks, ferociously warlike, had taken the Holy Land itself, all but extinguishing Christianity in the country that had given it birth. And they pressed on the East Roman Empire, long the bulwark between west and east, taking the rich province of Asia Minor. Alexius, emperor in Constantinople, had appealed to the west for help. But after centuries of invasions and war, the post-Roman states of west Europe were like armed camps, fractious and suspicious, bristling with petty armies any of which would have been dwarfed by the legionary forces of old. The Pope, spiritual leader of all these domains, longed to unify them in a great cause.

‘And what better ambition for a pope than a war against Islam?’ Ibn Hafsun murmured.

Moraima eyed Robert again. ‘I ask you once more: Must it be so?’

Robert said, ‘I hope not.’

‘You do?’

‘I would rather you and I were friends, than enemies.’

‘Then we will have to see how this little adventure of ours unfolds, won’t we?’ And she trotted back to her father’s side.

The older men exchanged bawdy glances, but Robert ignored them.