Who won the Battle of Clontarf?
Brian Boru's army won the Battle of Clontarf, fought near Dublin on Good Friday, 23 April 1014, against Leinster, Norse Dublin and Viking allies from overseas. It was a costly victory: the aged High King, his son Murchad and his grandson Tairdelbach all died that day, and Dublin itself was not taken.1
On Good Friday in 1014, on the shore at Clontarf near Dublin, the aged High King of Ireland met a coalition of the men of Leinster, the Norse of Dublin and Viking warriors from as far away as Orkney. The fighting lasted from the morning high tide until the tide came in again at evening, and when the beaten coalition ran for the sea, its ships were gone. In the hour of victory, according to later tradition, Brian Boru was cut down in his tent.2
For the wider story, see the military history of Ireland. Clontarf belongs to the same Viking world as Stamford Bridge, where a Norwegian army met its end in England in 1066, while Ireland's later turning points came at Kinsale in 1601 and the Boyne in 1690.
The rise of Brian Boru
Brian was born around 941 into the Dál Cais, a minor dynasty of the region around Killaloe on the lower Shannon. His elder brother Mathgamain was the first of the family to be recognized as king of Munster; when Mathgamain was murdered in 976, Brian took both his small kingdom and the kingship of Munster, and turned Munster into a unified and aggressive power.3
His campaigns into Leinster and Connacht brought him into conflict with Máel Sechnaill mac Domnaill, king of Tara and the most powerful ruler of the north. In 997 the two kings divided Ireland between them, Brian taking the southern half. The deal did not last. In 1002 Brian replaced Máel Sechnaill as high king, and within a few years every lesser king had submitted to him. His rule was never secure, though: Denis Casey, writing for Britannica, notes that it rested on frequent and massive displays of military force.4
Dublin and Leinster
Dublin had begun as a Viking stronghold on the south bank of the Liffey in the ninth century. By Brian's day it was a hybrid Hiberno-Scandinavian kingdom, increasingly Christian, and one of the great trading towns of northern Europe, with a large market in slaves. Irish kings no longer wanted to destroy it. They wanted to own it.5
In 999 the king of Dublin, Sitric Silkbeard, and the Leinstermen were crushed by Brian at Glenn Máma, and Brian sacked the town. He then restored Sitric as his subordinate king and later made Máel Mórda mac Murchada king of Leinster. Family ties bound the arrangement together. Máel Mórda's sister Gormlaith had been Brian's wife and was the mother both of Sitric and of Brian's son Donnchad, and a daughter of Brian was married to Sitric.6
The revolt of 1013
For a decade Dublin and Leinster stayed obedient. Then, in 1012 and 1013, Leinster broke with Brian and Dublin joined it. The Cogadh Gaedhel re Gallaibh, the great saga of Brian's wars, tells that the quarrel began at Brian's court at Kincora, where Máel Mórda had come with three pine masts as tribute and left in a rage. Whatever the spark, Brian besieged Dublin for about three months until Christmas 1013, while his son Murchad harried Leinster, and then withdrew.7
Over the winter the rebels looked overseas. Leinster and Dublin called on the Norse of the Scottish Isles, Man and Orkney, and by the spring of 1014 a large Viking fleet had gathered. Among its leaders were Sigurd, earl of Orkney, and a sea-king the Irish called Brotor and the sagas Brodir.8
The armies at Clontarf
In April 1014 Brian marched on Dublin and accepted a great pitched battle, something he had avoided for most of his career and a rare event in Irish warfare, which ran on ambushes, cattle raids and small fights. His army was mainly the men of Munster, with help from south Connacht. Máel Sechnaill was there too, according to several sources, but none of his followers appear among the dead, and he may have stood aside.9
Against them stood the Leinstermen, the Norse of Dublin and the overseas Vikings. The Annals of Ulster say the Vikings from overseas alone brought about a thousand men in mail coats. Neither side was purely Irish or purely Norse: Brian's army included Viking mercenaries and Gaels from Scotland and Man, and the earl of Mar fell on his side.10
A day of slaughter
The battle was fought on Good Friday, 23 April 1014, by the Julian calendar then in use, on the meadow of Clontarf on the north shore of Dublin Bay. Much about it is uncertain, because the oldest annals give no date, no place name and almost no detail. Modern scholars generally accept, Casey writes, that the Vikings first made a show of putting out to sea, as if abandoning Sitric, then came back to land, and that the fighting broke out near their landing place. Sitric himself, the Cogadh says, did not take the field but watched the battle from Dublin.11
The Cogadh describes a struggle from sunrise to evening, and its author tied the day to the tide: the foreigners came out to fight at high water in the morning, and when the tide returned at the end of the day, it had carried their ships away. For the 1867 edition, Dr. Haughton of Dublin calculated the tides of Dublin Bay for 23 April 1014 and found high water at about 5.30 in the morning and again just before six in the evening, which convinced the Cogadh's editor that its author drew on eyewitnesses.12
As the coalition broke, its men were trapped between the sea and the bridge over the Liffey. The Annals of Ulster say some 6,000 of them were killed or drowned, a number Britannica warns must be treated with caution, like all medieval body counts. The dead included Máel Mórda, king of Leinster, Sigurd of Orkney and Brotor himself. On Brian's side fell his son Murchad, Murchad's son Tairdelbach, who according to the Cogadh drowned at the weir of Clontarf with two of the foreigners locked in his grasp, and a long list of Munster and Connacht kings.13
The sagas of Iceland remembered the day too. In Njál's saga, Sigurd fights under a banner that brings death to whoever carries it; when no one else will take it up, the earl hides it under his own cloak, and soon after is speared.14
How many died at the Battle of Clontarf?
Nobody knows exactly. The Annals of Ulster say about 6,000 of the coalition were killed or drowned, and Britannica, which warns that medieval body counts need caution, puts the total dead at perhaps several thousand. Both sides lost their leaders: Máel Mórda, Sigurd and Brotor on one side; Brian, his son Murchad and his grandson Tairdelbach on the other.15
The death of Brian Boru
Brian was about 73 and did not fight in the line; Britannica credits the victory to his son Murchad. The later accounts, given some support by the 11th-century chronicle of Marianus Scotus, say that he stayed in his tent praying for victory, and that a small band of Norsemen fleeing the field stumbled on it, overcame his guard and killed him. The Annals of Ulster name the killer as Brotor, chief of the Scandinavian fleet.16
The Cogadh tells the scene in full. Brian's attendant saw a party of foreigners in mail approaching. Brian rose from his prayers and drew his sword. Their leader, Brodar, seeing that the old man had been praying, took him for a priest, until a companion who had once served Brian cried out that this was the king. Brian cut at Brodar's legs as the Viking split his head with an axe. Njál's saga has its own version, in which Brodir breaks through the ring of shields around the king and shouts that men should tell how Brodir felled Brian.17
The clergy of Armagh, with whom Brian had kept close ties, came for his body. The Annals of Ulster record that the successor of Patrick took the bodies of Brian and Murchad to Armagh, where they were buried in a new tomb while the community of Patrick kept vigil for twelve nights.18
Why was the Battle of Clontarf important?
Clontarf has long been seen as the battle that broke Viking power in Ireland. Historians are more cautious: Sitric kept Dublin, and the battle was as much a contest among Irish kings for the high kingship as a war of Irish against Norse. Its fame owes most to Brian's death in victory and to the legend written a century later.19
Brian's army probably held the field, but it could not press its advantage. Sitric kept his fortress of Dublin, which the Norse still held after their defeat, and the survivors of the Munster army went home. Terry Barry sees the battle less as a war of Irish against Vikings than as Brian's last attempt to force his lesser rivals to accept him as high king, and Brian's death brought a temporary decline of the Dál Cais.20
Viking raids on Ireland did almost cease after Clontarf, and the Norse turned their attention to England and Scotland: Cnut, son of Sweyn Forkbeard, became king of England in 1016. Dublin remained Ireland's chief trading town but never regained its old military power, though whether that was Clontarf's doing or part of a longer decline is unclear. Brian's son Donnchad ruled Munster for almost half a century, and Brian's descendants, the O'Briens, were counted among the great dynasties of Ireland.21› Battle of Stamford Bridge, 1066
How the legend was made
Most of what is told about Clontarf comes from the Cogadh Gaedhel re Gallaibh, a biography of Brian written about a century after the battle, when his descendants were again in power. It casts Ireland as the victim of endless pagan Viking invasions, Brian's dynasty as the heroes of the resistance, and gives almost half its pages to the build-up and the battle. That framing, of Christian Irish against pagan foreigners, Britannica calls simplistic and inaccurate, but it shaped nearly every later account.22
The Norse sagas, written more than two centuries after the battle, also treat Brian as a model Christian king. It was they, not the Irish texts, that cast Gormlaith as the woman who stirred up the war, and that picture slipped into many modern retellings. That the old king died on Good Friday fighting an army with a pagan contingent was not lost on any of his eulogists.23
In the centuries since, Clontarf has inspired poems, books and operas, and Brian became a symbol of national resistance, his harp an emblem of the Irish nation. The battle's millennium in 2014 brought a new wave of research and commemoration. Gaelic Ireland endured for nearly six more centuries, until its last great army was scattered by the English at Kinsale in 1601. In the same year as Clontarf, at the other end of Europe, Basil II destroyed a Bulgarian army at Kleidion. For more of the period, see the Middle Ages, and for the anniversary, 23 April in military history.24
