Sihtric scoffed. 'What do you think about that, Orm? That you, a Viking whose father worshipped trees, married a woman who was given a vision of God?'

Orm's discomfort deepened. 'Isn't that possible?'

'You know the truth already, Orm. You have seen it. You know all about the Menologium, and indeed the Codex of Aethelmaer. You know they were authored by an agent, or agents, intent on deflecting destiny. And now you have felt the cold hands of another history-meddler on your shoulder. Yes, another, Orm, I'm convinced of that. For your Witness seems opposed to the intervention made by the author of my Codex, doesn't she? We're caught in a war of meddlers, it seems.'

Orm stared at him. '"Meddlers"? That's a very human word.'

'I use it intentionally. There's nothing divine about the Weaver, Orm. He fiddles with history as a poor painter adds one brushstroke after another, never satisfied, for he has no true vision. And not only that, the Weaver fails to achieve his goals. William won at Hastings despite the Weaver's tinkering. No, Orm. The Weaver may not be human; he may be more – or less – than that. But I am convinced he is not God – and nor is your Witness.'

Orm's shock deepened. 'But how can he send words through time, into the head of another, save through a miracle? I have seen it myself, in Eadgyth. When she spoke her prophecy, they were not her words.'

'Trickery!' Sihtric said. 'Machinery! Working on my machines with the Moors has shaped my thinking, Orm. Think of it. You can build a machine that can throw a bolt miles. Waterwheels and canals that can turn a desert green! If you can do all that-'

'It's one thing to throw a bolt,' Orm protested. 'Another to throw words across centuries.'

'I can't imagine how it's done. But I also can't imagine what our machines will be capable of in five hundred years, or a thousand. I can put no limits on them, any more than I put limits on God.' His tone was edgy, uneasy.

'Is that heresy, priest?'

'Ah, that's a good question, and I'm a long way from any bishop who might be able to answer it for me.'

Orm stared at him, trying to pick his way through this morass of theology and speculation. 'You know, I used to talk about you with your sister, before Hastings. Even then we thought your ambition, that whole business of the Menologium, was destroying you. Turning you away from God. That was twenty years ago.'

'Well, perhaps you were right.' Sihtric laughed darkly. 'Nothing changes, does it?'

They were disturbed by a horseman, who came galloping in a cloud of dust. He was hot, bedraggled. 'Father! They said I would find you here.'

'Robert? What's wrong?'

'There has been an accident. A boy, Ghalib-'

Sihtric frowned. 'I know him – the son of a court favourite. Is he dead?'

'Not yet. But he is so badly injured he soon will be, that's for sure.' Robert told them what had happened. 'I got him out of the water – I tied off the damaged arm. I tried to save him, Father.'

Orm stood. 'We must sort this out,' he said to Sihtric.

'Of course,' Sihtric said. 'But, Robert, nobody will blame you if you tried to save this boy. And besides, the doctors here are better than you can imagine. Don't despair – leave that to me.' He winked at Orm. 'Let's go!'

They ran to their horses, and the three of them galloped away, leaving the scholars to clear away the drinks, to wipe the horse-raised dust from their plans and models and tables, and to return to their patient work on the tremendous arbalest.

Ibn Tufayl had ordered a hospital to be set up for his court in the ruined palace at Madinat az-Zahra. It was just a collection of tents, erected in the shelter of the walls of roofless rooms. Here Robert had to wait with Orm while Sihtric made inquiries about Ghalib.

After the hasty ride back from the arbalest, Robert was hot, dirty, his clothes still stinking of river-bottom mire and soaked through by Ghalib's blood. He tried to think.

How would it be if Ghalib died? Of course it wasn't his fault that Ghalib had fallen – it wasn't his fault that Ghalib had been mucking about on the waterwheel in the first place, and he had risked his own neck by dragging Ghalib out of the water. But the fact was he had been flirting with Moraima, a Muslim girl, and the two boys wouldn't have trailed around after them if not for that. Robert didn't want the death of Ghalib on his conscience. And he didn't want his burgeoning relationship with Moraima, such as it was, to be hauled into the light.

This was going to take some sorting out the next time he was in a confessional box.

Sihtric beckoned, and led them into one of the tents.

Robert was hugely relieved, if astonished, to find Ghalib sitting up in a chair. But his right arm terminated just below the elbow, a stump wrapped in clean white bandages. The boy looked pale, his gaze wandering; perhaps he was drugged. But he was alive, indeed he was conscious, and he didn't seem to be in any pain. And when he saw Robert, Ghalib's eyes filled with shame and anger.

Hisham stood beside Ghalib. Attendants fussed around, orchestrated by a portly man in pristine white robes. When he saw the visitors this man approached them. His face, round and sleek, looked as if it had been dipped in oil. He held his hands before him; small like a child's, they were scrubbed pink-clean, and showed no signs of calluses or scars. He said to Sihtric, 'Father. We have met before.' His accent was strange. 'My name is Abu Yusuf Yunus.'

'Ah, yes. The Egyptian.'

'My grandfather was Egyptian,' Abu Yusuf Yunus said stiffly. 'I am related by marriage to the Banu Zuhr family. I am a close friend of Abd al-Malik, while my father studied general medicine with his father, Muhammad Ibn Marwan Ibn Zuhr. Furthermore my grandfather studied with al-Zahrawi. We followed the prescripts of the al-Tasrif in treating this poor child…'

Orm grunted, impatient, and he pulled Sihtric aside. 'What's he babbling about?'

'Just establishing his credentials. Making sure I know who he is and where he stands. I told you, Orm, it's all family with the Moors. They're all Ibn this or Abu that, the son of him or the father of the other, their lineage carried like a flag. And these scholars are the same, all boasting about their academic lineage, who taught who what.'

Abu Yusuf Yunus, unable to make out their English words, walked towards the injured boy. In stilted Latin he said, 'The arm was almost severed below the elbow by the waterwheel's machinery – muscles, arteries and blood vessels all lacerated, the bone, too, all but cut through. To that extent the injury was like the result of a blow with a sword. But the lower arm was crushed, the flesh pulped and the bone ground up, as if the boy had been trampled, say.' Ghalib looked up at him dimly, and submitted passively as the surgeon began briskly to unravel the bandages on his arm. 'Your young Christian-'

'Robert,' Orm growled. 'My son.'

'Robert didn't save the boy's life merely by dragging him from the water, but by stemming the blood loss from the damaged arm. He tied it off with a bit of rope below the shoulder.'

'I did that,' Hisham said promptly. And he stared at Robert, as if daring him to contradict this naked lie.

'Then you are a hero, as much as Robert – more so, perhaps, for you used your brain rather than your muscles. Well done. Well done indeed.'

Robert looked away. Orm put his hand on his shoulder.

The bandages removed, Abu Yusuf Yunus exposed the wounded arm. Flaps of crudely cut skin were folded over the stump and stitched with gut. The seams leaked blood and a yellowish pus. Abu Yusuf Yunus clapped his hands. Attendants came bustling up with bowls of water and oils, and began to mop the wound. Ghalib twisted, but the attendants held him down.