‘Oh, more than that,’ Aethelmaer said, and he grinned to reveal rotting teeth. ‘Have you ever seen a siege engine that could swim under the sea? Have you ever seen an engine with wings - an engine that could fly? The Engines of God, we call them.’

Orm stared, shocked.

A young monk came in, an attendant from Maeldubesburg, carrying a tub of water and a cloth. ‘Time for your wash, Domnus.’

Aethelmaer grumbled, ‘Can’t you see I’m busy?’

The monk wouldn’t be put off. ‘You’re always busy. Come now.’

Aethelmaer acquiesced as the monk lifted his habit. His legs were white as snow, and one shin was afflicted by an ulcer, a suppurating, bloody, pus-soaked sore with the gleam of exposed bone. The stench of rotting flesh filled the room. Sihtric gulped, and Godgifu turned away. But Orm, a veteran of battlefields, had seen worse.

Sihtric said, ‘Tell me where this prophecy came from.’

Aethelmaer seemed to feel nothing at all as the monk swabbed out pus and cut back rotten flesh. ‘You’re aware that our comet is a repeat visitant.’

“That’s trivial,’ snapped Sihtric.

‘Then let me tell you that my “prophecy”, as you call it, was a product of the comet’s last visit to the earth.’

Sihtric, not to be outdone, hastily checked his own figures. ‘In the year of Our Lord 989.’

‘Exactly! And in that year, as the comet shone, a child was dumped at the gate of our monastery in Maeldubesburg: naked, no more than a few days old ...’

The monks had taken in the child, as was their custom, and found him a wet-nurse. As a private joke they called him Aethelred, after the then King.

It soon became apparent why the baby had been abandoned. As he grew he was a pretty boy, but quick to walk and slow to talk. He would spend hours on his own sketching figures in the dirt, but if put with the other children in the monastery school he would fight and scratch. ‘He was a damaged child,’ Aethelmaer said, ‘with something broken inside - broken or never formed.’

Nobody knew what to do with him until one inspired brother, seeing him scratching in the dirt, handed him a bit of chalk. At first his obsession with drawing was merely a way to keep Aethelred occupied - but it soon became clear that his drawings were more than just scribbles.

Sihtric guessed, ‘You mean these designs.’

‘Yes! You can see how detailed they are - look, it’s as if you can see inside the bodies of the engines. But there is no explanation, no lettering - save for blocks, like this one, of cryptic symbols, which nobody has been able yet to decode.’

Orm gazed at one such block, which was unhelpfully labelled ‘Incendium Dei’:

BMQVK XESEF EBZKM BMHSM BGNSD
DYEED OSMEM HPTVZ HESZS ZHVH

It meant nothing to him.