Bertgils leaned towards Belisarius and yelled in his ear, ‘These are old songs from the days of the great migration. We mourn our lost homeland. We mourn our ancestors. And for light relief we mourn the shortness of life.’

‘You’re a cheerful lot,’ Belisarius shouted back.

Bertgils grinned. ‘We are a people without an afterlife, at least except for those few of us who are successful warriors. We have a lot to be gloomy about.’

‘But you’re Christian now.’

‘There is that,’ Bertgils said dryly. ‘Belisarius, about this prophecy - I do think we need something a bit more substantial to take before Aethelred and the witan. For instance, if this threat of “dragons” is real - where is it to come from? Aethelred knows all about the other German kings, and the Picts to the north, and the British to the west.’

Belisarius mused, ‘It might come from another direction altogether.’ He turned to the computistor. ‘Boniface, speaking of the Menologium, what of the later stanzas - which presumably describe a further future? For instance, that business in stanza seven of how the dragon will fly west. What lies west of Britain? There are legends, centuries old, of lands to the north called Thule - could there be any truth in such a tale?’

Macson was dismissive. ‘Everybody knows there is nothing to the west but ocean.’

‘Actually that isn’t true,’ Aelfric said. ‘The monks have found that out.’

‘How?’

‘By sailing there.’

Over the centuries some monks, emulating Cuthbert, in search of ever deeper solitude, had set off on eremitic quests into the western sea. They journeyed from Lindisfarena, its parent house on Iona, and monasteries in Ireland, sailing in fragile little boats of wood and leather called currachs. Many of them failed to return - but some did, telling of lands they found scattered across the face of the ocean.

Boniface said, ‘This went on for centuries. And there grew among the monks a tradition that somewhere out there to the west was to be found the Promised Land of the Saints. And so they went further and further.’

This culminated in the seven-year voyage of Saint Brendan, founder of many monasteries, who was supposed to have sailed west to an island of sheep, an island of birds, an island of fire, an island of grapes. He came to a pillar of glass that rose out of the sea. He found the apostle Judas sitting on a rock. And so on.

‘What rubbish,’ Macson said.

‘But Brendan returned to tell the tale,’ Belisarius said. ‘Clearly he found something.’

Bertgils asked, ‘What are you getting at, Belisarius?’

‘The Menologium talks later of sea voyages. What if the threat is to come, not from the land, but from the sea? None of your kings is looking that way.’

‘But who would come?’ Bertgils asked. ‘The Franks? Offa is on good terms with them. And the ocean is a hard road to travel.’