Sihtric snorted. ‘You were there, Viking. You know how close it came. If Harold had eliminated Tostig as I urged him - if common cause could have been found between Harold and Hardrada - if only the winds had shifted earlier and William had landed in midsummer, when Harold was waiting with a fresh army - at the battle, if William had stayed down when he fell - if not for that arrow which brought down Harold himself, if the shield wall could have held just another hour ... There are so many ways it could have happened. And we would be attending Harold’s Christmas feast.’

‘And if any of these ifs had come about? What then?’

Sihtric pulled his lip. ‘Well, with Hardrada dead and William fallen, England would have faced no serious outside threat for a generation. There’s always the question of the succession. Tricky, that. If Harold had lived long enough he might have married his son by the sister of the northern earls into the family of Edward. Then, you see, he could have united in his grandson the Godwine blood, the northern earls, and the line of Alfred and the Cerdicings, the oldest royal dynasty in Europe. Who could challenge the legitimacy of that?’

‘I’ll tell you who,’ Orm said. ‘Harold’s children of his first family, by Edith Swanneshals.’

‘Perhaps, perhaps,’ Sihtric said. ‘But it’s a game that will never play out.’

And Edith, rather than siring kings, had had to identify her husband’s butchered corpse on his last battlefield.

‘But then?’ Orm asked, intrigued by this unreal history despite himself. ‘If Harold had won, if his children were athelings not refugees - and then, and then?’

And then, the priest said, with its southern neighbours beaten and reduced to disarray, England would have turned north.

‘Think of it,’ Sihtric said ruefully. ‘Longships laden with English goods would sail to the east into Constantinople and the heart of Asia, and to the west they would reach the unknown continents where the Vikings founded Vinland. England is already richer than any of the petty kingdoms of Frankia, Germany or Italy; in time this federation of the north would have overwhelmed the wretched south. England’s last ties to the ruins of the Roman empire would be cut. And these ambitious soldier-Christian brutes like William, thwarted in England, might have abandoned their dreams of murderous crusades in al-Andalus and the Holy Land.’

‘And your prophecy would be fulfilled,’ Orm said. ‘An empire in the north.’

‘Yes. Or a republic.’

Orm frowned. ‘What do you mean by that?’

‘You spoke to me of how the Vikings planted a new kind of society out in the ocean. Where the landowners and the wealthy men gather to make mutual decisions about the future.’

‘The althings.’