‘Not military. Evangelical.’ He told them of Saint Francis of Assisi, founder of his order, whom Thomas himself had, thrillingly, met as a novice. ‘The first rule Francis wrote for our order was a command for a global mission to “all peoples, races, tribes, and tongues, all nations and all men of all countries, who are and who shall be”. Perhaps these Engines will enable my brothers to advance their most holy mission - even if not a life is taken with them.’

Joan said, ‘So we share common goals, my family and your order.’

‘Oh, yes.’

‘So what do you think we should do about this, Thomas?’

‘You could write to this cousin in Cordoba, or travel there. Or you could come to England - perhaps we could bring her there.’

Joan frowned. ‘The Muslims would have us out of Jerusalem for good. It’s not the best time to leave, chasing a dream. And I’m not sure if writing back to my Moorish cousin about this matter is advisable. For now, let us study the matter further. Subh can wait.’ But she frowned again at her letter. ‘You know, there are so many puzzles here. Thomas, what of this phrase, Incendium Dei?’

Thomas said, ‘Something Subh’s own ancestress, Moraima, evidently remembers of the lost Codex.’

‘“The Fire of God.”’

‘More than “fire”,’ Thomas said. ‘It is a word with passion. It means conflagration. Ruin. Perhaps it is a phrase associated with the bit of the manuscript from which Robert tore his corner . . .’

A thought occurred to him. He pawed through his notes once more, looking for the transcription of the ripped-through phrase with the coded words. All those incomplete letters, I, V, M - was it possible that Subh’s Latin phrase would complete that puzzle?

But he was exhausted by the heat. With apologies to Joan, promising to discuss all this further, he gathered up his documents and made his way to bed, his head buzzing with the enigma of the Incendium Dei, the Fire of God.

XIII

XIII

Among Subh’s many admirable qualities was an antipathy to wasting time. And so, on only his second day in Seville, Peter was to meet Moorish scholars who would inspect the fragmentary weapons plans he had retrieved from the wreckage of the schemes of long-dead Sihtric.

He was in no state for this, with his hair and skin caked with dust and his clothes stiff with stale sweat. At Subh’s suggestion, or perhaps it was an order, he took a bath, Moorish style. For the price of an English penny he had the dirt scraped and sweated out of his skin, he was shaved and his hair chopped back, and he had the ache of the mule ride kneaded out of his back by a masseur, a huge Moor with biceps like a bull’s thighs.