Anyhow she liked the slog. It was like rowing or running, hard work that made your sweat break out and your lungs pump, and dissolved your thoughts, your doubts and worries and fears.

And she liked it up here. She took a break, straightening a stiff back. The sky was empty of cloud, a rich blue dome. Before her the green-clad mountains that walled the fjord rose almost vertically from the water, marching to a horizon softened to blue by sunlit mist. She could see bare patches of cleared forest working their way up the slopes, places where the people had built their farms, slowly turning the wood that cloaked the mountains into houses and halls and ships.

Today the water was still as oil. Boats of all sizes slid like insects, sails gently billowing, oars plashing, dragon prows proud, utterly dwarfed by the mountains around them. This was a gentle spring day, but even when the winters were at their worst the fjord's salty waters, branching from the ocean, never froze. Indeed it was in the winter that the whales came gliding into the fjord from the ocean in search of herring. The fjord was a larder – and a highway. In this place of deep-cut valleys and steep ridges there were few roads; the small and scattered communities of one fjord communicated with the next by boat.

It was said that the fjords were as deep as the mountains around them were high, though how anybody could possibly know that she had no idea. Perhaps it was a memory of the giants from the edge of the world who were said to have built this fjord, and the hundreds like it along this Viking coast. Well, the giants had done a good job, Gudrid thought. The fjords had to be deep, for otherwise there would be no room for the whales.

Her back a little less sore, she spat on her palms, picked up her axe and went back to her trunk-stripping.

About noon her husband came climbing up the slope. In the misty air his stocky frame looked dark, solid. His first words were a grumble. 'I should have known I'd find you up here. I had to ask Birgitta.'

She straightened up and took a heavy draught of water from her leather pouch. 'A man reduced to asking his sister-in-law where his wife is. What a wretched life you lead, Askold.'

They exchanged these blows almost listlessly. After five years of marriage their sparring was routine.

'So what do you want? Couldn't you persuade Birgitta to cut you some meat?'

He dug into a pocket and pulled out a parcel wrapped in a bit of skin. He threw it to the ground at her feet. 'I brought you your food. And I came to tell you your father's back from Britain.'

Frowning, she knelt and unwrapped the parcel. It was a slab of mutton and half a loaf of bread. 'All right, I'm sorry.' She broke the bread in two, tore the meat with her teeth, and handed the larger portions to Askold. 'Here.'

He sat beside her, solid, round-shouldered, his hair greasy. With ill grace he took the food. Sitting side by side, not touching, they ate.

Askold had always been a bit short, solidly built, not the brightest – 'muscle all the way to the top of his head', her father liked to joke. He wouldn't have been her first choice of husband. But he had been the first to come courting, in his clumsy way, when she was fourteen. Since then he had stuck with her, and she had never seen him do a deliberate unkindness to another – although she had heard he could be brutal when he went raiding. He wasn't a bad man, then. Probably.

But he was disappointing, she thought drearily. Sex with him had been painful the first few times, then for a while vaguely pleasurable – but quickly, like much else in their lives, it had become a chore. Nowadays they would lie together of a night, and he would spend himself into her, and they would roll apart and sleep, all without exchanging a single word, even without kissing. It had been like this since she was sixteen years old.

And when the sons refused to blossom in her womb, their relationship turned dull. He had stayed with her. Perhaps he loved her in his way. But it was a cold, deadened love. Surely the love of Ulf and Sulpicia, six generations back, had been much more fiery than this.

It didn't help that these days the fjords swarmed with other men's sons. Sons were a source of pride, a sign of virility, a promise of wealth in old age. And all those sons wanted their own homes.

That was the trouble, her father said. The fjords were full, they were already living halfway up the mountains, and still more sons popped from the women's loins. That was why the people were sailing off to Britain, or even further.

These thoughts reminded her why Askold had said he had come here. 'You say my father is back?'

He nodded and pointed. 'Look, you can see his ship. Good trading with the British. Whale ivory in exchange for wool and hunting dogs and slaves. Plenty of good places for a landing, he said.'

She knew what that meant. Good places to raid.

'Oh,' Askold said. 'He told me to tell you. The island you've mentioned before – where the story of Ulf and Sul – Sulpi-'

'Sulpicia.'

'Where all that's supposed to have happened.'

She guessed, 'Lindisfarena?'

'That's the place.'

'It didn't happen there. There's just supposed to be a copy of the prophecy there. The Menologium of Isolde…'

Askold waited, staring into the misty distance and chewing his meat, until she shut up. He hated to be corrected.

'Tell me what my father said.'

'Not much more than that. They landed, did a bit of trading with black-robed monks, left. Bjarni said he couldn't see why he would ever go back.'

Gudrid was disappointed. 'He said that?'

'Oh, and he brought a slave back. Got him cheap. A useless-looking lad who puked all the way back across the ocean.'

That was something, she thought. Slaves often saw more than their masters imagined; perhaps he could tell her about Lindisfarena.

She had finished her bread and meat. She stood, stretching her arms. 'Askold, are you busy? I've a spare axe, and water.'

Askold glanced at the trees she had been stripping. 'I've nothing better to do.' He got to his feet, took the better of the two axes she had brought, and set to work.

As they laboured through the spring afternoon, they exchanged barely a word.

V

The scriptorium was a quiet, dark, silent room, smelling of old vellum and sour ink, its walls lined with stacks of books. Aelfric was alone here, working by the sputtering light of a goose-fat lamp. This inky womb was her favourite place, she thought, in all the world.

The nib of her pen scratching softly at smooth vellum, Aelfric laboured over her copy of the fourth stanza of the Menologium of the Blessed Isolde:

The Comet comes/in the month of October.

In homage a king bows/at hermit's feet.

Not an island, an island/not a shield, a shield.

Nine hundred and seven/the months of the fourth Year…

Her pen was cut from a goose quill. The ink, which the monks called encaustum, came from an oak tree gall. You crushed the gall in vinegar, thickened it with gum, and added salts for colour. The ink was thick and caustic and bit into the surface of the vellum – and so you had to take great care with your lettering, for a mistake when made could not be unmade (though it could be disguised as embellishment, as Aelfric had quickly learned).

The vellum on which she wrote was the skin of a calf, soaked in urine to remove the hair and fat, then scraped clean, stretched on a frame and smoothed with a stone. There was something wonderfully earthy about it all. She could smell the monks' piss, and even when the book was complete it would have to be bound in a wooden frame to stop it curling back into animal hide.

Dom Boniface, the old computistor who was her tutor, said Aelfric, a mere novice with less than a year's experience, should regard it as an honour to be working on the Menologium. It was the small library's 'hidden treasure', as he put it, in among the Bible commentaries, hagiographies and histories, and books of grammar and computistics and chronologies. For this brief and enigmatic document supported the abbot's claim for the Blessed Isolde to be confirmed as a saint by the Pope, thus adding to Northumbria's already glittering array of celestial warriors. And the words themselves were precious. They had almost been lost, Boniface told her, committed to the memory of illiterate pagans for several generations before being transcribed once more.