Fair-haired Norsemen, burly Danes; some were light coloured, some dark and swarthy. Many, she judged, were nothing more than pirates. Yet these were the allies that her Leinster king had called upon to strike at Brian Boru. She could have wished he had found other sorts of men.

As she made her way to church, she wondered what to do. Was she making a terrible mistake? For a start, it was now clear that her move back to her brother's in Dyflin had been premature, and probably pointless. King Brian would not be troubling Rathmines this time, because he was coming up the other side of the Liffey, far away. Her eldest son had already gone back to the rath to watch over the livestock that morning. But the real question was, why hadn't she gone to Harold? Her son had been unequivocal. "For God's sake go," he had told her. "You've no complaint against Harold. The man has nothing to do with Brian Boru. You've honoured my father's memory longer than you need. Haven't you done enough for Leinster?"

She didn't even know for certain where Harold was now. Was he at his farmstead or with the O'neill king, perhaps? His offer had been clear. She must come to him by Easter, but not afterwards. If the man was in any way reasonable, she thought, a few days or weeks wouldn't matter, but there was something in the Norseman's nature that indicated he would not budge.

Irritating though it was, she rather admired him for it. If she came to him after Easter, his mind would have swung closed, like a heavy wooden gate. The offer would be gone. She knew it.

Even if she could accept what he had done before, even if she could accept that she was in the wrong, Caoilinn didn't like being told what to do. By making the offer in the way he had, he was asserting his authority, and she couldn't see how to get out of it.

Her pride still made it difficult for her to let him win and she meant to put off the decision as long as possible until she could think of a way of getting even.

She was also a little nervous. So far, no one had troubled Harold about his equivocal position. People knew that Morann had secured protection for his friend, just as, in turn, Harold had mitigated the damage to her own estate. But now there was going to be a great battle; whoever won would suffer terrible casualties. If she were seen leaving Dyflin now to go across to a man under Brian's protection, and the men of Dyflin were to succeed in smashing Brian, they might not take kindly to her desertion. There could be ugly I reprisals. Alternatively, of course, if she stayed where she was and Brian won, she could be trapped in a burning Dyflin. But the worst aspect of the business lay in the bluntly cynical proposition her son had put to her just before he departed.

"As a family, you know, it would be best if we had a foot in each camp, so that we could help each other whatever the outcome. I'm in the Leinster camp, of course, but if you were with Harold a"

"You mean," she said bitterly, "you'd want me in Brian Boru's camp?"

"Well, not exactly. Only with Harold being Morann's friend, and Moranna" He shrugged.

"It doesn't matter, Mother, since I know you won't."

Curse them all, she thought. Curse them. For once in her life, Caoilinn truly didn't know what to do.

The church service for Palm Sunday had already started as the solitary figure made his way along the wood quay towards the boat. He walked with a slight stoop. He was alone. His companions in the longship were elsewhere. They were, in any case, only companions for this voyage; after this, he might see some of them again, or he might not. It was all the same to him. He had no use for friends. At I this moment, his face wore a twisted smile.

He had lived in many places. His three sons had been raised in Waterford; but he had fallen out with them some years ago and scarcely seen them since.

They were fully grown. He owed them nothing. One thing, however, he had given them, when they were still children.

He had been trading at the small harbour on the River Boyne.

There had been a woman there; he had stayed awhile.

And because he was swarthy, the Celtic-speaking people at the port had called him Dubh Gall-the dark stranger. Even the women had called him that: "My Dubh Gall." It had amused his shipmates. They had carried the name back with them. And before long, even in the Viking port of Waterford, his children were known as the family of Dubh Gall. The name had ceased to amuse him now. His companions in the longship called him by his real name: Sigurd.

For the last few years he had led a wandering life, sometimes working as a mercenary. He had arrived in Dyflin the night before with Brodar, who had been hired by the Leinster and Dyflin kings. And the reason why he was smiling was not because the pay and the prospects for looting were excellent, but because he had just made a pleasing discovery.

Harold the Norwegian, the red-haired crippled boy, was still living.

He had never forgotten about Harold; from time to time down the years, the lame Norwegian had come into his mind. But there had been so many other matters to attend to, and fate had not brought them close again.

The nature of his feelings had also changed. As a boy, he had felt a burning need to avenge his family's name: the Norwegian had to be killed.

As a man, this old desire had become spiced with cruelty. He took pleasure in contemplating the pain and humiliation he could inflict upon the young farmer. In recent years, it had just become a piece of unfinished business, a debt unpd.

But now he had found himself on the way to Dyflin to take part in a battle. The circumstances were perfect. Naturally, during the voyage he had thought about Harold. But it had been when he first stepped on to the wood quay, where they had met before, that all the sensations of his boyhood had suddenly come back at him with a rush. This was destiny, he concluded. The Norwegian must die. When that was duly accomplished, he thought, he would go back to Waterford and seek out his sons, who had never known about this business, and tell them what he had done and why and, perhaps, even be reconciled with them.

It had not taken long to find out about Harold in Dyflin. At first, when he had asked about a lame farmer, he had received some blank looks; but then a merchant in the Fish Shambles had smiled in recognition.

"Do you mean the Norwegian? The man with the big farmstead out in Fingal? There's a rich fellow. An important man. Is he a friend of yours?"

Though he had traded, and fought, and stolen all over the northern seas, Sigurd had never become rich.

"He was, many years ago," he had answered with a smile.

The merchant had soon told him all he needed to know: that Harold was a widower, the size of his family, the location of the big farmstead.

"He has powerful friends," the merchant said. "The O'neill king is his protector."

"You mean he might be fighting against us?"

"I do not think he would do that. Unless he was obliged to. Possibly his sons might."

If Harold and his sons were in the battle on the other side, so much the better. He would make his way towards them. If not, then during or after the battle, he would find them at the farmstead. He would take them by surprise, with luck; kill the sons as well and end their family line. It would be a fine thing indeed to bring not only Harold's head but those of his sons back with him across the sea.

No wonder, then, that Sigurd wore a twisted smile. He was looking forward to the battle.

Morann reached King Brian's camp at noon that day.

The Munster king had decided to encamp on the northern side of the estuary. To the east lay the headland of the Ben of Howth. To the west, not far off, was the Tolka stream, running down to the Liffey's shore, a small wood, and the little hamlet of Clontarf. "The bulls' field" the name of the hamlet meant, though if there had been any bulls in the pasture before, their owners had wisely removed them before the army of Brian arrived. It was a good choice. The ground sloped, giving the defenders an advantage, and anyone approaching from Dyflin across the Liffey still had to wade across the Tolka to reach the camp.

On entering the camp, Morann received his first surprise. For instead of encountering Munster or Connacht men, the first part of the camp he passed through consisted entirely of Viking Norsemen, whose fearsome faces he had never seen before. Seeing one of Brian's commanders whom he knew, he asked him who they were.

"They are our friends, Morann. Ospak and Wolf the Quarrelsome. Fighting bands, much feared on the seas, they say." He grinned. "If the Dyflin king can call in friends from across the water, King Brian's just returning the compliment." He laughed.

"You have to admit, the old man's lost none of his cunning."

"They look like pirates," said Morann.

"Dyflin has their pirates, and we have ours," the commander replied, with satisfaction. "Whatever it takes to win, Morann: you know Brian. Where's the King of Tara, by the way?"

"He is coming," said Morann.

He found King Brian at the centre of the camp, sitting on a silk- covered chair in a large tent. With his white beard and deeply lined face, the ageing king looked a little tired, but his spirit, as ever, was sharp and he was in a good humour. Morann apologised quickly for Harold's absence. "His horse tripped when we were crossing a stream and he fell. With his crippled leg, you know, I sent him home." And though King Brian gave him a cynical look, he seemed to have too much else on his mind to pursue the matter further. The first thing he wanted was news of the O'neill king, and he listened intently as Morann gave him a careful report. At the end, Brian looked thoughtful.

"He will come then. That is clear. He said he could not let me lose. That is interesting. What do you think he means?"

"What he says. No less, and no more. He won't break his oath, but he will sit out the battle and preserve his own strength while yours is wasted. Only if he thinks you're in danger of losing will he intervene."

"I think so, too." Brian gazed into the distance for a moment. He seemed sad. "My son will command the battle," he remarked. "I'm too old." He glanced up at Morann with a flash of shrewd irony. "It is I, however, who will plan the battle."

Certainly the old king seemed confident. He had already sent a large detachment of his army away to raid parts of Leinster that its king had left unguarded. He chatted briefly about these developments with Morann, then fell silent; and the silversmith was about to take his leave when Brian suddenly reached onto a table beside him and took up a small book.

"Look at this, Morann. Did you ever see anything like it?" And opening its pages he showed the craftsman the astonishing illustrations that the monk of Glendalough had done. "Send in that monk," he called out, and a few moments later, Morann was pleased to see Osgar. "You know each other. That is good. You shall both stay by my side." He smiled.

"Our friend here wanted to go back to Glendalough but I told him he's to stay here with me and pray for victory." Brother Osgar looked rather pale.

"Don't worry," the king said to him genially, "the fighting won't reach here." He glanced at Morann mischievously. "Unless, God forbid, your prayers fail."

At the end of the following day, they saw the great host of the King of Tara arrive from the north. They pitched camp on the slopes below the Plain of Bird Flocks, some distance away but within sight.

The next morning, the King of Tara arrived with several of his chief men. They went into Brian's tent and spent some time there, before returning. That afternoon, as Brian was making a tour of the camp, he saw Morann.

"We have had our council of war," he told him.

"Now we have to draw them out to fight on our ground."

"How will you do that?"

"Anger them. By now they'll be getting reports of the damage my raiding parties are doing behind them. Then they'll see the flames here. If the King of Leinster thinks I'm going to destroy his kingdom, he won't sit in Dyflin for long. So, Morann," he said smiling, "it's time to tease him."

Harold saw the smoke on Wednesday morning.

There was no sign of Caoilinn. The fires seemed to be coming from the southern edge of the Plain of Bird Flocks. Then he saw the plumes of smoke appearing farther east; then flames, breaking out on the slopes of the Ben of Howth. By the afternoon, the fires extended right across the southern horizon. It was probably as well that Morann had persuaded him to go back to the farmstead. He made what preparations he could. There were a few slaves left there, so he armed them and together they put up a barricade in front of the main house- though whether they could do anything if a raiding party of any size came along, he seriously doubted.

The next morning, the fires were closer. The breeze from the south-west was blowing the smoke in his direction. Around noon, he saw smoke away to his right, then behind him. The firings were encircling him. Early in the afternoon, a horseman came in sight, cantering towards the farmstead. He seemed to be alone. He stopped by the entrance and, cautiously, Harold went towards him.

"Who owns this place?" the man called out.

"I do," said Harold.

"Who are you?" the man demanded.

"Harold, son of Olaf."

"Ah." The man smiled. "You're all right, then."

And wheeling his horse round, he rode away.

Once again, as he gave a sigh of relief, Harold gave thanks to his friend Morann for protecting him.

But if the farmstead appeared to be safe, there were other urgent matters to worry about. He had to assume that Caoilinn was still in Dyflin. The army of Brian Boru and the fires lay between them.

There was little chance of her reaching him now. If there was a battle and Brian won, he would quite likely burn down the town as well. What would become of Caoilinn then? Even if, as it certainly appeared, she had decided to reject his offer, was he really going to leave her in the burning town and make no attempt to save her?

Then in late afternoon a small cart came towards the gate, and huddled in it he saw the family of a farmer from south of him. Their farm had been torched and they were looking for shelter, so of course he took them in. Had they any news of what was happening at Dyflin, he asked.

"Brian Boru and the King of Tara are both drawn up to right," the farmer told him. "It could start any time."

Harold considered. Morann had been so insistent he should stay at the farmstead; and Morann always had good reasons for everything he did. But for the moment anyway, the farmstead was safe; whereas his sons were with the O'neill king who was about to go into battle. Could he really stay here instead of riding to fight beside his sons? Shouldn't he at least arm himself and ride towards the battle. He smiled to himself: there had been a time when he had trained himself to become a formidable warrior.

Should he keep his promise to Morann, or break it? He wasn't sure. That evening, he cleaned and sharpened his axe and his other weapons. Then, for a long time, he remained staring into the darkness at the glow of the fires on the horizon.

Good Friday, 23 April 1014. One of the most holy days of the year. They marched out of Dyflin at dawn.

Caoilinn watched them from the ramparts. She was one of a large crowd. The day before she had watched fearfully as a big raiding party had even had the cheek to cross the Liffey by Ath Cliath, under their very noses, and set light to farmsteads out at Kilmainham and Clondalkin. She had been worried they might go found to Rathmines as well, but they had dashed back across the river before the Dyflin defenders had managed to get a war party together to stop them. The fires over Fingal and out at Howth had been bad enough, but this last humiliation had been too much. It was said that the King of Leinster's sister had given him a piece of her mind about it. Troublemaker though the royal lady was, Caoilinn would have agreed with her. During the night, the Fingal and Kilmainham fires had all died down, but there was no knowing what fresh ones Brian's men might start. It was almost a relief, therefore, to see the army move out.

But it was a fearsome sight. And most terrifying of all, the Leinster people agreed, were the Vikings from across the seas.

It was their armour. The Celtic people of the island no longer stripped for battle as their ancestors had done. The Leinstermen who marched out of Dyflin wore long, brightly coloured vests or leather padded tunics over their shirts; some had helmets, most carried the traditional painted shield, strengthened with bosses of iron. But splendid though this battle gear was, it did not compare with that of the Vikings. For the Vikings wore chain mail. Thousands of tiny links of iron or brass, tightly woven and riveted, and worn over a leather undershirt, that stretched to below the waist or even the knee, the chain mail was heavy and slowed the warrior down, but it was very hard to pierce.

In their use of chain mail, the Vikings were only following a practice that had evolved in the Orient and was now in use across much of Europe. But to the people of the western island it made them look strangely grey, dark, and evil. This was the armour worn by most of the men from the longships.

It was a huge force that marched out of Dyflin and went across the wooden bridge. Though their armour was different, the weapons carried by Irish Gaedhil and Viking Gaill were not so unlike, for as well as the customary spear and sword, more than a few of the Celtic warriors carried Viking axes.

There were some archers with quivers of poisoned arrows, and there were several chariots to carry the great men. But the battle would be fought not by manoeuvre but by massed lines in hand-to-hand fighting. Watching them go, Caoilinn did not try to keep count, but it seemed to her that there were well over two thousand men.

There was still a pale mist on the water as they crossed the bridge and for a little way on the other side it looked as if they were floating, like an army of phantoms, along the opposite bank. To the right, farther off, she detected movements in the camp of Brian Boru; and on the slopes in the distance, she could make out the vague mass of the army of the King of Tara.

The question now was, what should she do? The way was open before her. After the army had passed through, the town gates had been left open. The bridge was clear.

On the far bank, the army would soon be two miles away or more and the camp of the O'neill king was at a similar distance. If she chose to do so, she could take the old road to the north and be at Harold's farmstead in less than two hours. Once the battle started, however, who knew what would happen?

At the least, the way could be barred again. This might be her last chance.

Should she go? Her son thought so. Did she want to go? Over the last few days she had thought of little else. If she were to leave to marry someone, she certainly didn't know a better man than Harold. She'd make him a good wife, too; and that knowledge was also an attraction. She desired him. It was futile to deny that. Did she love him? When she had seen the smoke and flames from Fingal and thought of the Norseman and his farmstead, she had experienced a pang of fear, and a little wave of tenderness for him, before she had reminded herself that, as he was under the King of Tara's protection, he and his farm were probably safe.

But now, as she watched the men of Dyflin go out to battle, she decided that whatever her own feelings, and whatever her eldest son might wish, her most important duty must be to secure the best chance of success for her younger children. She must be calculating and, if necessary, cold.

Today was Good Friday. With luck the battle would be decided I by nightfall. If Brian Boru was defeated, then marriage to Harold would be foolish. But if he won, that would leave one day before Easter in which to go to the Norseman. Harold might be killed, of course. He might also think her timing opportunistic. That couldn't be helped. Easter was Easter. As a mother, there was only one sensible course to follow.

So it was, a short time later, that the lone figure of Caoilinn on a chestnut mare, followed by her two younger children, rode slowly out of Dyflin and across the wooden bridge. Once across, she followed the track up to a vantage point on some raised ground from which she could watch the outcome of events.

Depending on how the battle went, she could either go with all haste to the man she loved, or retire discreetly back to Dyflin.

"Let us pray, children," she said.

"What for, Mother?" they asked.

"A clear victory."

I.

They had drawn up the battle in three great lines. In the centre, the front line was made up of the men of Brian's own tribe, led by one of his grandsons; behind them came the Munster host, with the Connacht men in the third line. On the two wings were the Norse contingents of Ospak and Wolf the Quarrelsome. Opposite them, advancing across the Tolka, the Leinster and Dyflin forces were in similar battle lines.

Morann had never seen anything like it. He was only a few feet away from King Brian. Around the old king, his personal guards had formed a protective enclosure, ready to form their shields, if necessary, into an impenetrable wall. The slight slope gave them a good view of the battle which was to take place below them.

The lines of troops were packed so thickly and were so deep, it seemed to Morann that you could have driven a chariot over their helmets from one wing to the other.

Both sides had unfurled their battle banners, dozens of them, which were streaming in the breeze. At the centre of the enemy line, a huge wind sock in the form of a red dragon seemed ready to devour the other banners, while over the centre of Brian's line, a black raven banner flapped as though screeching in fury.

It was as soon as the enemy had waded across the Tolka stream that the war cries began, starting with bloodcurdling shouts from individual warriors or groups, but then gathering into a single huge roar from one line, only to be echoed by an answering roar from the other. Again the roar came as the two lines advanced, and again. And then, from the Celtic centre came the great opening shower of javelins. A second shower of spears followed the first; and then, with a mighty roar, the two front lines rushed forward and, with a huge bang, crashed together. It was a terrifying sight.

Morann glanced at the little group in the enclosure.

The king was sitting on a broad bench covered with furs. His eyes were fixed on the battle ahead, his face so alert that, despite his lines and his white beard, he seemed almost youthful. Beside him, waiting for an order, stood a faithful servant. Behind him, his face now paler than a ghost, was Osgar the monk. Several of the guards also stood ready to carry any messages he might wish to send. He had already sent one or two messages to his son, as to troop dispositions, but now, for the time being, there was nothing to do but watch and wait.

If Osgar the monk looked frightened, Morann could hardly blame him. Would the enemy break through and sweep towards them? Scar-faced Brodar's fearsome Vikings appeared to be making terrible inroads on one part of the line. But though it seemed to sag, Morann saw the standards from the centre suddenly start to move, creating an internal bulge in the line as they went towards the most hard-pressed point.