But if the trading post and its little monastery provided poor pickings, the Vikings could see at once that the site had potential. The old Celtic road system converged nearby, to use the river crossing; the tidal harbour was protected and the land was good. The area around the rath was defensible, too.

The Norwegians had settled. Though known to history as Vikings, or Norsemen, they often referred to themselves as Ostmen-men from the east.

Soon, a little way upstream from the ford, a huddle of their timber-and-wattle huts and a Viking cemetery had appeared by the riverside. Learning that the dark pool was called Dubh Linn, the Norsemen produced their own version of the name: Dyflin. Nor was the Viking presence limited to their small port.

Scandinavian farmsteads had spread across the territory north of the Liffey estuary. The farmstead of Harold's family was one of them. And so it was that the old Plain of Bird Flocks had acquired an additional Celtic name: Fine Gall, the Foreigner's Place-Fingal.

When Harold's ancestor and the Norwegian fleet had arrived at Dubh Linn that day, the men at the rath had not tried to give battle. Since a single Viking longship carried anywhere from thirty to sixty fighting men, resistance would have been futile. And it was thanks to this reception that from that day on, the fair-haired Norwegians had taken the people of the trading post under their protection.

Not that the last century and a half had been peaceful.

Life was seldom peaceful for long in the Viking world.

But to Harold, the coastal plain of Fingal and the small town of Dyflin were delightful I places. And when today, as they rode down the long slope towards the Liffey, a bank of grey clouds moved across the sky, darkening the I landscape, it had not affected his happy mood a bit.

The merchant ship had arrived from the harbour of Waterford, on the island's southern coast. There were a number of ports round the coasts of Ireland-nearly all of them settled by Vikings and bearing Viking names. Though Viking fighting ships were long and sleek, their merchant vessels had a bulge at midship which allowed them to carry a considerable amount of cargo in their bellies. The Waterford ship had brought a cargo of wine from southwestern France, and Harolds father was going to buy a few barrels. While his father talked to the merchants, Harold had been admiring the ship's handsome lines when he heard a voice from somewhere behind him.

"Y. Hey. Cripple boy. I'm talking to you."

As Harold turned, he saw a pale, black-haired boy, of nine or ten he guessed-about his own age-standing in a crowd. Though one or two of the crowd glanced in his direction when they heard the boy call out, nobody seemed particularly interested, but the boy's eyes were fixed upon him intently. He had spoken in Norse, not Irish, and as Harold had never seen him before, he supposed he must have arrived on the ship. He wondered whether to ignore the rude stranger, but that might look like cowardice, so he limped over to him.

The boy's eyes were gazing at his legs as he approached.

"Who are you?" Harold asked.

"That's your father, isn't it?" the boy said, ignoring his question and nodding towards Harold's father, who was standing some way off. "The one with red hair, like you." Yes.

"I didn't know," the boy said thoughtfully, "that you'd be a cripple. Your other leg's good, isn't it?

Just your left that's bent."

"That's right. Not that it's any of your business."

"Perhaps not. Or perhaps it is. What happened?"

"A horse fell on me." A horse his father had told him not to go near. The horse had bolted with him, then jumped over a ditch and fallen.

His left leg, trapped under the horse, had been smashed.

"Have you any brothers?"

"No. Only sisters."

"That's what they told me. It'll always be crooked, your leg, won't it?"

"I should think so."

"Pity." He gave Harold a strange smile.

"Don't misunderstand me. I don't care about your leg. I hope you're in agony. I'd just prefer if you weren't a cripple when you grow up."

"Why?"

"Because that's when I'm going to kill you. My name's Sigurd, by the way."

Then he turned round and walked swiftly back through the crowd; and Harold was so astonished that, by the time he tried to hurry after him, the dark-haired boy had vanished.

"So you know who he was?" Harold had been telling his father about the strange incident. Now his father was looking grave.

"Yes." Olaf paused. "If this boy is who I think he is," he explained, "then he comes from Waterford. He's a Dane."

The first Norwegian settlement at Dyflin had only been in existence ten years when the Danish Vikings arrived. With the northern half of England in their grip, they had been prowling round the Irish coast looking for places to raid and settle. The trading post that their fellow Vikings from Norway had established on the Liffey looked appealing. They arrived in force and told the Norwegians: We've come to share this place." For a generation after that, the port had gone about its business under various masters: sometimes Norwegian, sometimes Danish, sometimes both ruling together. Though there were still plenty of fair-haired Norwegian settlers like Harold and his family in the area, it was the Danish Vikings who ruled in Dyflin and many other Irish ports nowadays.

"But why should he want to kill me?" the boy asked.

His father sighed.

"It goes back a long way, Harold," he began. "As you know, the Ostmen of Dyflin have always had an enemy. I mean the High Kin go."

Even now, six centuries after Niall of the Nine Hostages had laid claim to the High Kingship of Tara, his descendants, the O'neill as they were called, still held the High Kingship and dominated the northern half of the island. The Vikings had never been able to settle on the northern and western coasts which the O'neill directly ruled; and the existence of the independent Viking port on the LifTey had always annoyed them. For it hadn't been long before the Viking ruler there had started behaving like one of the provincial Irish kings. The last King of Dyflin, as he called himself, had married a princess of Leinster; his territory had included all of Fingal. "And he would have liked to control all the land up to the River Boyne and beyond," Harold's father had once told him. No wonder the mighty O'neill looked at the newcomers with distaste. Every ten years or so, since the settlement began, the O'neill High King had come to try to kick the Vikings out. Once, eighty years ago, the Irish had managed to burn the place down and the Vikings had left, though only for a few years. On their return, between Ath Cliath and the pool of Dubh Linn the Norsemen had built a new settlement on the ridge with a strong wall and stockade, and a stout wooden bridge across the river. But the present O'neill king was a determined man. A year ago, in a big battle up at Tara, he had beaten the Norsemen of Dyflin. Harold's father had not gone to that fight; but afterwards, he and Harold had watched the Irish king's line of chariots crossing the long wooden bridge over the Liffey. The king had stayed in Dyflin for several months; but then he had left, taking away whole cartloads of gold and silver, and Dyflin was back under a Viking ruler. The port had to pay tribute to the Irish king now, but otherwise it was business as usual.

"Long ago," his father began, "when Dyflin was still Norwegian, the High King attacked us one year.

And he paid some Danes to help him. Did you ever hear the story?"

Harold frowned. There were many sagas about Viking battles and heroic deeds, but he could not recall hearing this one. He shook his head.

"It's recorded," his father said quietly, "but it's not a popular story nowadays." He sighed. "There was a particular party of Danes who'd been raiding the northern islands. They were bad people. Even the other Danes avoided them. The High King got word to them, and offered them a reward if they'd help him attack Dyflin."

"And they came?"

"Oh yes." Olaf grimaced. "We beat them off. But it was an ugly business. My grandfather-he was a child at the time-lost his father in that raid." He paused. Harold listened carefully. He hoped that his ancestor had not died dishonourably.

"He was killed after the battle was over," his father went on. "A Dane came up and stabbed him in the back, then ran away. The Dane's name was Sigurd, son of Sweyn. Even his own men despised him for that deed."

"It wasn't avenged?"

"Not then. They got away. But years later, when my grandfather was on a ship trading in the northern islands, he saw a longship in a harbour and was told it belonged to Sigurd and his son. So he challenged them to fight. Sigurd was an old man by then, though still strong, and his son was my grandfather's age. So Sigurd agreed to fight on condition that, if he was killed, my grandfather would fight his son as well. And my grandfather swore: "I will have both your heads, Sigurd, son of Sweyn, and if you had more sons I would take those away with me, too." As it was evening then, they agreed to fight the next morning, as soon as the sun was over the sea.

So at dawn my grandfather went to where their ship was; but as he came near, they pushed away from the shore and started rowing out to sea. And they laughed at him and shouted insults. Then my grandfather ran back to his own ship and begged them to follow Sigurd. They refused and as he was only a young man, there was nothing he could do. But they'd all seen what happened, and Sigurd and his son were known as cowards all over the northern seas.

"My grandfather got word of them from time to time down the years. They were on the Isle of Man, that lies between ourselves and I Britain, for a while, then in England, in York. But they never came to Dyflin. And after my grandfather died, we heard no more of them. Until five years ago when a merchant told me that Sigurd's grandson was in Waterford.

I thought about going down there, buta" He shrugged. "It's been too long. I thought that the grandson in Waterford mightn't even know about the business. I put it behind me and I've never worried about it again-until today."

"But Sigurd's family didn't forget."

"It seems not."

"If you choose to forget, why doesn't this boy?"

"It's his family who were disgraced, Harold, not ours. He seems to be prouder than his ancestors, at least. They never cared about their evil reputation, but he obviously does. So he must avenge their shame by killing you."

"He wants to cut off my head and show it to everyone?" Yes.

"So I'll have to fight him one day?"

"Unless he changes his mind. But I don't think he will."

Harold considered. He felt a little frightened, but if this was his fate, then he knew he must be brave.

"So what should I do, Father?"

"Prepare." His father looked down at him gravely for a moment. Then he smiled and clapped him on the back. "Because when you fight, Harold, you're going to win."

Goibniu the Smith glared at the mound. Then he grabbed his son's arm.

"Will you look at that!"

The sixteen-year-old boy stared. He wasn't sure what he was meant to see, but it was obvious that his father was furious about something. He tried, surreptitiously, to discover what point exactly his father's eye was fixed upon.

The prehistoric mounds above the River Boyne had not greatly altered since the time of Patrick. Here and there a further subsidence had occurred. The entrance doorways were all hidden now; but in front of them, a quantity of white quartz stones were still strewn across the ground, glistening when the sunlight caught them. In the River Boyne below, the salmon and swans went about their quiet business as if they themselves had been there when the Tuatha De Danaan had gone to their bright halls within the ridge. But something had evidently displeased the eye of Goibniu. Unlike his distant ancestor, Goibniu had the use of both his eyes. But when he was considering something, he had a trick of closing one eye and squinting through the other, which seemed in the process to become unusually large. Men found his gaze disconcerting. And not without reason. He never missed anything.

"Look at the top, Morann." Goibniu held his son's arm in a vicelike grip, as he pointed impatiently.

And now the young man saw that the top of one of the mounds had been disturbed. Near the middle of the grassy dome, several ragged piles of stone indicated that someone had tried to break into the tomb from above.

"Barbarians! Heathens!" the craftsman cried.

"It was the cursed Ostmen who did that."

About a century ago, a party of Vikings, curious to discover how the great tombs were constructed and whether they contained any treasure, had spent several days trying to break into one of them. Unaware that there was an entrance hidden in the side, they had tried to come in through the top.

"Did they get anything?" Morann asked.

"They did not. The stones are huge as you go farther down. I looked. They gave up." He relapsed into silence for a moment and then burst out, "How dare they touch the gods!"

Strictly speaking, this was inconsistent. Though the craftsman's family, like many others, had held out for several generations after Patrick's ministry before they grudgingly took the new religion, they had been Christians for nearly four centuries now. On feast days, Goibniu went to the church of the little monastery nearby and solemnly took communion. His family had always supposed that the smith was a faithful son of the Church-though you could never be sure with Goibniu. But like most of the faithful on the island, he still felt an affection and a need for the ancient ways. Paganism never dies entirely. Most of the pagan rites of seedtime and harvest, of course, had already been incorporated under new names into the Christian calendar; and even some of the old inauguration rites of the kings, including that of mating with a mare, were still a fond memory. As for the old gods, they might not be gods anymore-"idols and lies," the priests declared. They might be only myths, to be recited by bards. Or they might, with the Church's blessing, be accounted for as ancestral heroes, extraordinary men, from whom dynasties like the mighty O'neill could claim descent. But whatever they were, they belonged to Ireland, and it was not for the Viking pirates to profane their sacred places.

Morann said nothing. His father had dismounted, and together they walked round the tombs in silence. In front of the largest stood the great stone with its strange carved spirals, and the two of them paused to stare at the mystical object.

"Our people used to live near here," the smith remarked moodily. It had been an ancestor two centuries ago who had moved two days" journey away, to the north-west, into the region of small lakes which the family presently occupied.

Evidently, for Goibniu, the stone with its cosmic spirals represented a kind of homecoming.

And it was only now that his son ventured to ask the question which had been puzzling him since his father's outburst began.

"If you hate the Ostmen so much, Father, then why are you taking me to live with them?"

It seemed a natural question; but in answer, the smith looked at him bleakly, muttered, "It's a fool I have for a son," and relapsed into silence. Only after a long pause did he deign to explain himself further.

"Who is the greatest power on this island?" the smith asked.

"The High King, Father."

"He is, indeed." He nodded. "And isn't it true that for generation after generation, the High Kings have tried to kick the Ostmen out of Dyflin?" He pronounced the Norse name sullenly.

"They did, Father."

"But last year, when the High King won a great battle at Tara and came down to the Liffey-when he could have kicked them out, and they could have done nothing about it at all-he let them stay and took tribute instead. Why would he do that, do you think?"

"I suppose because it suited him," his son suggested. "He'd be better off taking their tribute than kicking them out."

"That is true. A port is a valuable thing. The Ostmen's ports bring in wealth. You're better off keeping them than destroying them." He paused. "I will tell you something else. Is the power of the O'neill as great today as once it was?"

It is not.

"And why is that?"

"They quarrelled amongst themselves." Up to a point this was true. Long ago, the mighty royal house had split into two branches, known as the Northern and Southern O'neill. Generally these two had skilfully avoided dissension by alternating the High Kingship between them. But in recent generations there had been bickering. Other powers on the island, especially the kings of Munster in the south, had been chipping away at the authority of the O'neill in the time-honoured manner. One young Munster chief, named Brian Boru, seemed ready to stir up trouble with scant respect for any of the settled kingships. The O'neill were still strong-hadn't they just defeated the Vikings of Dyflin?-but the lesser Irish kings were watching. Like a huge bull, the great power in the north was showing signs of age.

"Perhaps. But I will suggest to you a deeper cause.

The O'neill are not to be blamed. They could not have foreseen the consequences of their actions. But when the Ostmen first began to attack our shores, the O'neill were so strong that the Ostmen could not establish a single port on the coasts of their land.

Not one. All the Ostmen's ports lie farther south. Yet that strength may have been a curse. Can you tell me why?"

"The ports bring wealth?" his son offered.

"And wealth is power. How do you imagine Niall of the Nine Hostages became so mighty before Saint Patrick came? By raiding Britain. He had treasure and slaves to reward his followers. The Ostmen are pirates and heathens, mostly. But their ports are rich. The more ports a king has, if he can control them, the more riches and power he has. That is the weakness of the O'neill now. The ports are not on their lands. That's why they need Dyflin, the richest port of all."

"So that's why you want me there?"

"It is." Goibniu looked at his son seriously. Sometimes he thought the boy was too cautious, too careful. Well, if so, it might be for the best. He gestured to the tomb and its broken roof again. "I'll never like the Ostmen. But Dyflin is the future, Morann, and that is where you're going."

She was dancing. Such a slim, dark little thing-white legs like sticks and a tangle of black hair tumbling down her back-a shuffle it was, she danced, this way and that; and he, watching her all the time, the child in the street. Caoilinn was her name; his, Osgar. And as he watched her, he wondered.

Was he to be married that day?

Wherever you looked in the Viking town of Dyflin, you saw wood. The narrow streets that rolled up and down the uneven slopes were made of split tree trunks; in the winding alleys and footpaths you walked on planks. All the lanes were lined on both sides with blank-faced wattle or picket fences behind which, in their narrow plots, could be seen the thatched roofs of the rectangular wicker- walled dwellings or timbered halls of the Norsemen. Some tenements contained pens for pigs, hens, and other livestock, some were given over to workshops; and the wooden walls around them were to deter thieves or attackers or, like the sides of a ship, to keep out the winter wind from the wide, grey estuary and the open seascape beyond.

Enclosing this twenty-acre wooden village was an earth rampart topped with a wooden palisade. Beyond the palisade, on the waterfront, was a stout wood quay, against which several long- ships were tied. Just upstream was the long wooden bridge and past that the Ford of Hurdles. The Irish people still mostly called the place by its old name, Ath Cliath, even if they often crossed by the Viking bridge instead of the Celtic ford. But though Caoilinn was Irish, she called the wooden township Dyflin, because she lived there.

"Shall we go over to the monastery?" She suddenly turned her green eyes on him.

"Do you think you should?" he said. She was nine and he was eleven.

He had a better sense of what was fitting.