Belisarius could see that for a thegn like Bertgils, to be close to such a king as the Butcher gave a chance of advancement, but was also supremely dangerous. And this father certainly seemed to have the measure of his daughter. 'I'm getting the impression Bertgils is a wise man. And it is through your father that you will win us an audience with the King?'

'My father is on the witan. The King's council.'

'So,' Macson snapped, 'he sent you to masquerade as a man inside a monastery. Your husband should protect you.'

Aelfric's nostrils flared. 'I have no husband.'

'Why? Are your legs withered, your womb dry?'

Belisarius interrupted quickly, 'Aelfric, you should understand that it is no accident we are here. Macson has come all this way because he is descended from one of the protagonists of the legend which spawned your Menologium in the first place. Or at least he believes he is.'

Her eyes widened. 'You are a grandson of Wuffa? Or Ulf? But you are British.'

'One of those brutes – yes,' Macson spat back. 'I am descended from Sulpicia, the British woman who was raped by one or both those barbarians.'

'There was no rape,' Aelfric said. 'Wuffa loved Sulpicia. Ulf tried to take her from him, and the prophecy. They fought.'

'Who told you this story?'

'It comes from the descendant of Wuffa who brought the prophecy here in the first place.'

'We will surely never know the full story,' Belisarius said emolliently. 'Perhaps these are all partial truths.'

Aelfric seemed fascinated by Macson now. 'So your family kept this story alive. Did your grandfathers write it down?'

'We were illiterate,' Macson said with a kind of perverse pride. He tapped his forehead. 'We remembered, man-woman.'

'And now you've come here for what? Revenge?'

'It is as good a motive as any,' Macson said coldly.

'The British are good at nursing grudges,' Aelfric said. 'Even now they call this country the Lost Land in their tongue. Boniface says its loss was a punishment from God for wickedness and corruption. Easier to blame the Germans than to accept your sins!'

Macson glowered, and stalked away.

The dragon ship was fifteen paces long. She was laid down on a keel cut from a single oak timber, its curve so gentle the centre was only the length of a forearm lower than the end points. It was this carefully shaped keel that gave the ship the shallow draught that made her so easy to beach, and also gripped at the water when underway to balance the pressure from the sail and keep her from capsizing. The ship's hull was of oak too, thick polished planks laid down so they overlapped each other, and held in place by wooden pegs.

Gudrid had sailed in such ships all her life, of course – but only in the fjords, or around the coast. Never before had she sailed into the open sea, and out of sight of land; never had she taken the sail road.

In the days before the raid Gudrid helped scrub the boat clean, scrape her hull and repair its caulking, and then they lowered the hull under the sea water so that the salt could kill off rats and worms and fleas.

The men hung their war shields on racks along the ship's sides, and they embarked. When she got a chance Gudrid took her turn at the oars. She worked as hard as any man. But the woollen sail with its bright checks billowed overhead; they were fortunate with the winds, needing to resort to the oars only occasionally.

The slave Rhodri was taken along on the voyage. There was always bailing, shit-shovelling and other chores to be done, and he might have useful local knowledge at the end of the journey. But Rhodri spent most of the journey with his head hanging over the side of the boat, and Bjami got very little work out of him. He was too stupid even to avoid vomiting into the wind, and as the men wiped his bile from their faces they were all for pitching him over the side, and Gudrid had to argue for his life. She made sure that he knew he was in her debt.

Her father showed her the elements of navigation. The Norse mostly stayed within sight of land, and he showed her crude maps drawn on vellum and parchment, with key landmarks to be sighted. To get to Britain, however, it was necessary to cut west across the open sea. Sightings of the sun and the stars were used to keep to a line running dead straight east to west. The principle was simple; if you ensured the pole star never dipped or rose in your sky, you could not be travelling either north or south over the surface of the curving world. You could also use the wheeling of the sun and moon to find your way. It was harder to tell how far east or west you travelled, but estimates were made by dead reckoning, as days were counted and logs dropped over the side to gauge their speed.

The more experienced sailors had deeper skills. By the colour of the water, the fish and sea birds they saw, even the scent of the air, they seemed able to 'smell' their way across the sea, all the way to the land. Gudrid envied them.

Gudrid marvelled at how the ship and her crew performed. The ship's very hull twisted in response to the sea's buffeting. A product of centuries of sailing the fjords, she was like a sleek animal, like an otter or a whale, perfectly adapted for her environment. And her companions, slim forms dimly seen through ocean mist, looked like the dragons of myth, strange creatures from the edge of reality, hurtling across a forgiving sea to a new junction in history.

The coast of Britain came in sight within half a day of Bjarni's first guess. Their position was soon established with the maps, and they began scudding south towards Lindisfarena.

Aelfric managed to arrange a meeting with her father, Bertgils the thegn, at the King's coastal citadel of Bebbanburh. Perhaps an audience with the King would follow.

But Belisarius was aware that as they waited for this meeting the days slipped by, and May gave way to June, the month specified in the Menologium stanza, when disaster was due to strike.

At Aelfric's suggestion Belisarius took along a gift for the King. He chose one of his most precious books, the comedies of the Greek Aristophanes, centuries old, said to be only a few copy-generations younger than the playwright's own manuscript.

Aelfric/Aelfflaed discarded her habit before travelling. Dressed in leggings and a long tunic, her hair tied back under a cap to hide her tonsure, she looked more womanly than Belisarius had expected. He noticed that Macson, who seemed to have got over the 'lies' Aelfric had told him, looked at her with renewed interest. She instructed them they must all call her 'Aelfflaed' during the visit, for her monkish career was supposed to be a secret from all at the Butcher's court. Belisarius would try, but he could only think of her by her brave pseudonym.

Bebbanburh was half a day's ride north along the coast from the causeway to Lindisfarena. The citadel was a massive misshapen lump of hard black rock, right at the edge of the ocean, with tidal wrack and barnacles crowded at its foot. Looking up, shielding his eyes against a bright sky, Belisarius saw a bristling line of fortifications around the summit plateau. They ascended a flight of steps cut into the rock. The climb was lung-straining for them all, but poor old Boniface had to be practically carried up.

Belisarius wondered how this mighty rock had come to be here at all, what immense chthonic force, divine or natural, had thrust it up through the fabric of a gentler landscape of dunes and sea grass. Belisarius liked to think his mind was roomy enough for a glimmer of wonder at the marvels of the physical world, which served as a stage for humanity's petty dramas.