‘For I have secrets in this room,’ said Sihtric. ‘Secrets I’ve shared with no one - certainly not the vizier. You want to know why I stay here, why I live among Moors who speak of Allah, and Christians who speak no Latin? Why I have let myself become locked into a damaging relationship with a snake like the vizier . . .’ He glanced upwards to the darkened ceiling, as if challenging God. ‘You see, Orm, I’ve found a rent in the tapestry of time. Another one, a third or a fourth, to add to the ripping-open of the Menologium of Isolde, and the Codex, and your poor wife’s Testament. And through that rent I have glimpsed horror. But from that horror I have conceived an ambition as big as the world, Orm. It is nothing less than the final defeat of Islam, and the preservation of Christendom into the far future. What higher goal can there be than that? Is a man justified in giving up his very soul to achieve such an aim?’

A month had passed since the incident of Ghalib and the waterwheel. A month in which Orm had continued to learn uncomfortable details of Sihtric’s murky career in Cordoba. And now, he said, Sihtric was going to tell him the whole truth. Orm wasn’t sure he wanted to hear it. He shivered, obscurely frightened. ‘You always did talk in riddles, priest.’

‘Well, the whole business is a riddle, isn’t it? But then it always was.’ Sihtric got to his feet and crossed to the wall. He pulled away a crate stacked with books, then hauled aside a shabby hanging to expose tiles with geometric patterns, a kind of trefoil in black and white that, repeated, covered the wall area. Sihtric dug his fingers into the edge of a tile and with some effort picked it away from the wall. ‘I have a habit of biting my nails,’ he said. ‘Makes this tricky.’ A hatch, concealed by tiles, now hinged down to reveal an iron door. Sihtric extracted a key from his robe, unlocked the door, and it swung back to reveal a compartment inside the wall. Sihtric began to rummage in the dark space, which Orm saw was full of books, scrolls, heaps of parchment and vellum. There was a musty smell, of rot and age.

Sihtric drew a flat wooden box from the wall compartment. He placed this on a table, unpicked ties of copper wire, and opened up the box like the covers of a book. Leather hinges creaked slightly, and a smell like stale meat flooded the room.