‘In a way. Orm’s arrival upset everything - in particular the relationship between Sihtric and Ibn Tufayl.’

‘So it all went wrong. Then what?’

‘Ibn Tufayl tried to destroy the machines Sihtric had made, and to eliminate the scholars who had worked with him. He wanted it all for himself. He dreamed of being more than a vizier, lady.’

Subh nodded, matter-of-fact. ‘He wouldn’t have been the first. I take it he didn’t achieve his ambition?’

‘No. As they fought he burned himself to death, along with Sihtric and Orm, and the plans for the machines. All this took place in the palace of Madinat az-Zahra.’

Subh looked at him shrewdly. ‘Not all the plans were lost. Or you would not be telling me about this now.’

‘You’re perceptive,’ he said. ‘No, not all of them. Ibn Tufayl doesn’t seem to have been very competent. There are hints of personal weaknesses in the records - I suppose that doesn’t matter. He was certainly not efficient in his elimination of Sihtric’s work. I was able to find traces in the archives. For instance, one young clerk survived the vizier’s cull, and, in bitterness, wrote down all he remembered to thwart the vizier’s purpose. There are similar relics. It’s all very fragmentary - most of it is just the point of view of one junior clerk - but—’

‘You have these fragments?’

‘Some of them. And, more than this - the blaze did not destroy everything. Moraima and Robert escaped. Between them they took away the Codex of the Engines of God - the original designs brought by Sihtric to Spain.’

‘And what did they do with them?’

‘The two of them fell out. They could not agree. The plans were buried - but what was buried was fire-damaged and not complete. One corner had been torn away by Robert, perhaps intentionally, perhaps not. This fragment contained the secret of God’s Fire. Possibly - it is said. And it may be that Robert took away another treasure, another prophecy entirely, called the “Testament of al-Hafredi”. I know little about that. But as for the rest of the engine designs, a man called Ibn Hafsun buried them for Moraima.’ He thought it over. ‘I suppose he may have been an ancestor of your Alonso the Fat.’

‘How ironic that would be,’ Subh said drily. ‘And where did he bury the plans?’

Peter hesitated. ‘Under the floor of the great mosque in Seville. In fact I have seen a fragment of memoir by Ibn Hafsun, in which he specifies exactly where the Codex can be found.’

Subh laughed. ‘Now you’re being absurd. Peter of Toledo, you must know that in a country where war has washed back and forth ever since Tariq crossed the strait, there are legends of buried treasure under every rock.’

‘But it may be worth looking,’ Peter said softly.