'Where I come from bridges are washed out all the time,' Bistami said. 'People just build another one.'

'Yes, but this is so much more elegant. I wonder if they put any of this down on paper. I haven't seen any books of theirs. The libraries left behind here are terrible, all account books, with the occasional bit of pornography. If there was ever anything more it's been burned to start fires. Anyway, the stones tell the story. See, the stones were cut so well there was no need for mortar. The iron pegs you see sticking out were probably used to anchor scaffolding.'

'The Mughals build well in Sind,' Bistami said, thinking of the perfect joints in Chishti's tomb. 'But mostly the temples and forts. The bridges are usually bamboo, set in piles of stone.'

Ibn nodded. 'You see a lot of that. But maybe this river doesn't flood as much. It seems like dry country.'

In the evenings Ibn Ezra showed them a little model of the hoists the Romans must have used to move the great stones: stick tripods, string ropes. The Sultan and Sultana were his principal audience, but many others watched too, while others wandered in and out of the torchlight. These people asked Ibn Ezra questions, they made comments; they stayed around when the Sultan's cavalry head, Sharif jalil, came into the circle with two of his horsemen holding between them a third, who had been accused of theft, apparently not for the first time. As the Sultan discussed his case with Sharif, Bistami gathered that the accused man had an unsavoury reputation, for reasons known to them but left unsaid – an interest in boys perhaps. Apprehension very like dread filled Bistami, recalling scenes from Fatepur Sikri; strict sharia called for thieves' hands to be cut off, and sodomy, the infamous vice of the Christian crusaders, was punishable by death.

But Mawji Darya merely strode up to the man and yanked him down by the ear, as if chastising a child. 'You want for nothing with us. You joined us in Malaga, and need only work honestly to be part of our city.'

The Sultana nodded at this.

'If we wanted to, we would have the right to punish you in ways you would not like at all. Go talk to our handless penitents if you doubt me! Or we could simply leave you behind, and see how you fare with the locals. The Zott don't like anyone but themselves doing things like this. They would dispose of you quickly. I tell you now, this will happen if Sharif brings you before me again. You will be cast out of your family. Believe me 'glancing significantly towards his wife – 'you would regret that.'

The man blubbered something submissive (he was drunk, Bistami saw) and was hauled away. The Sultan told Ibn Ezra to continue his exposition on Roman bridges.

Later Bistami joined the Sultana in the big royal tent, and remarked on the general openness of their court.

'No veils,' Katima said sharply. 'Not the izar nor the hijab, the veil that kept the caliph from the people. The hijab was the first step on the road to the despotism of the caliph. Mohammed was never like that, never. He made the first mosque an assembly of friends. Everyone had access to him, and everyone spoke their mind. It could have stayed like that, and the mosque become the place of… of a different way. With both women and men speaking. This was what Mohammed began, and who are we to change it? Why follow the ways of those who build barriers, who turned into despots? Mohammed wanted group feeling to lead, and the person in charge to be no more than a hakam, an arbiter. This was the title he loved the most and was most proud of, did you know that?'

'Yes.'

'But when he was gone to Heaven, Muawiya established the caliphate, and put guards in the mosques to protect himself, and it has been tyranny ever since. Islam changed from submission to subjugation, and women were banned from the mosques and from their rightful place. It's a travesty of Islam!'

She was red cheeked, vibrant with suppressed emotion. Bistami had never seen such fervour and beauty together in one face, and he could hardly think; or, he was full of thought on several levels at once, so that focus on any one stream of ideas left him fluttering in all the others, restless and inclined to stop following that tributary; inclined merely to let all rivers of thought roll at once.

'Yes,' he said.

She stalked away towards the next fire, squatted down all at once in a fluff of skirts, in the group of handless and one handed men. They greeted her cheerfully and offered her one of their cups, and she drank deeply, then put it down and said, 'Come on then, it's time, you're looking ratty again.' They pulled out a stool, she sat on it, and one of them knelt before her, his broad back to her. She took the offered comb and a vial of oil, and began to work the comb through the man's long tangled hair. The motley crew of their ship of fools settled in around her contentedly.

North of the Ebro the caravan stopped growing. There were fewer towns on the old road to the north, and they were smaller, composed of recent Maghribi settlers, Berbers who had sailed straight across from Algiers and even Tunis. They were growing barley and cucumbers, and pasturing sheep and goats in the long fertile valleys with their rocky ridgelines,

Not far inland from the Mediterranean. Catalonia, this had been called, very fine land, heavily forested on the hills. They had left behind the taifa kingdoms to the south, and the people here were content; they felt no need to follow a dispossessed sufi sultan and his motley caravan, over the Pyrenees and into wild Firanja. And in any case, as Ibn Ezra pointed out, the caravan did not boast food enough to feed many more dependants, nor the gold or money to buy more food than they already were from the villages they passed.

So they continued on the old road, and at the head of a long narrowing valley they found themselves on a broad, dry, rocky plateau, leading up to the forested flanks of a range of mountains, formed of rock darker than the rock of the Himalaya. The old road wound up the flattest part of the tilted plateau, by the side of a gravelly streambed almost devoid of water. Further along it followed a cut in the hills, just above the bed of this small stream, wandering up into mountains that grew rockier and taller. Now when they camped at night they met no one at all, but bedded down in tents or under the stars, sleeping to the sound of the wind in the trees, and the clattering brooks, and the shifting horses against their harness lines. Eventually the road wound up among rocks, a flat way leading through a rockbound pass, then across a mountain meadow among the peaks, then up through another tight pass, flanked by granite battlements; and then down at last. Compared to the Khyber Pass it was not much of a struggle, Bistami thought, but many in the caravan were shivering and afraid.

On the other side of the pass, rockslides had buried the old road repeatedly, and each time the road became a mere foot trail, switchbacking at sharp angles across the rockslides. These were hard going, and the Sultana often got off her horse and walked, leading her women with no tolerance for ineptitude or complaint. Indeed she had a sharp tongue when she was annoyed, sharp and scornful.

Ibn Ezra inspected the roads every evening when they stopped, and the rockslides too when they passed them, making drawings of any exposed roadbeds, coping stones or drainage ditches. 'It's classic Roman,' he said one evening by the fire as they ate roast mutton. 'They knitted all the land around the Mediterranean with these roads. I wonder if this was their main route over the Pyrenees. I don't suppose so, it's so far to the west. It will lead us to the western ocean rather than the Mediterranean. But perhaps it's the easiest pass. It's hard to believe this is not the main road, it's so big.'

'Perhaps they're all that way,' said the Sultana.