The ground fell away, and the novices’ upturned faces were like coins on a table. They were clapping and cheering. The landscape opened up beneath him, and he saw the shape of the limestone ridge from which he had launched, and the plain before it, and the ruined village where engines crawled and gunpowder flashed.

His heart raced with excitement, and a bit of fear, and he felt his loins tense up. He had admitted to nobody, not even his confessor, the extraordinary erotic thrill this hurling into the air gave him. If he could never have a woman, at least he had this. And as the air washed around him the face of Grace Bigod swam into his mind, elegant, cold, sneering.

Already the crossbow was running down, but it had lifted James high enough for his purpose. He had to work quickly. He pulled strings to latch the crossbow, and others to lock the wings, outstretched with the feathers closed and banked. Then, with a grunting effort, he leaned forward, and the leather cradle into which he was strapped pivoted, so that he was suspended beneath the wings, belly down.

He glided forward, wings rigid as a coasting seagull’s. He was falling, of course, falling like a dead leaf. But he should reach the battlefield, and that was enough for him to do his job.

He looked down at the ruined village. More hapless novices were defending a ‘fortress’, crudely constructed of heaped-up stone from the village. They were equipped with weapons of a conventional sort, crossbows, longbows, arquebuses and cannon, and had even had some rudimentary training in using them.

But huge machines crawled relentlessly towards the village, spitting fire. James made out the gun carriage nicknamed the ‘organ-pipes’. Between two massive wheels was suspended an axle with a triangular cross-section. On each of the axle’s three faces had been fixed a dozen cannon, in a row like the pipes of a church organ. These fired together, lit simultaneously by spring-loaded flints. Then, dragged by unhappy mules, the engine trundled forward until the axle turned and another bank of cannon was brought into play.

Other engines displayed different solutions to the challenge of multiplying fire. Here was a great wheel set horizontally, mounted with cannon spread radially like the petals of a daisy, which turned and spat fire when each gun was brought to the right position.