23 April 1014

A carved bust of the Irish king Brian Boru looks out from the Chapel Royal outside Dublin.

Like many battles from the early Middle Ages, the exact events that took place on a low plain just north of Dublin on Good Friday, 1014, are shrouded in later legend and obfuscation. What is certain is that the man who claimed the kingship of all Ireland, Brian Bóruma mac Cennetig, better known in the Anglicized form Brian Boru, defeated the combined armies of Laigin (Leinster) and the Dublin Vikings. By the battle’s end, Brian lay dead, but all the later annals of the Irish saw the victory as a hard-won triumph against the looming threat of conquest by what were called the ‘Foreigners of the West’.

There is much to disentangle in the history of the Battle of Clúain Tarbh, or Clontarf, a place not even mentioned in some of the near contemporary annals. Ireland in the early eleventh century was a kaleidoscope of tribal, clan and regional loyalties, broken up into small kingdoms, with settled Viking communities around the coast and the main Viking centre at Dublin. Brian, overking of Dál Cais, king of Munster, who rose to power across the last third of the tenth century, had succeeded by 1011 in imposing some kind of suzerainty on the rulers of much of the island, beginning with his home province of Munster. This was a unique achievement, but the restless, bellicose nature of Irish clan politics doomed Brian to fight in defence of his claim. In 1013, the Leinstermen and the Vikings of Dublin rejected Brian’s authority and embarked on a violent rebellion, pillaging and laying waste territory ruled by Brian’s vassals. Brian was obliged to take up the challenge posed by the Viking king of Dublin, Sigtrygg. He gathered forces from Munster and neighbouring Mide, ruled by Máel Sechnaill, and from among the men of Connacht. They all set out for Dublin, appropriately, on St Patrick’s Day.


Like the conflict between Alfred and the Danes, the subsequent battle was once seen as a decisive turning point in the struggle between the pagan Scandinavians and the Christian Irish, but the truth is certainly more complicated, since the Leinstermen were also Christians, and there were many Viking converts. The real explanation for the legend surrounding Brian’s victory at Clontarf lies in the long list of Viking friends and allies summoned by Sigtrygg once he heard of Brian’s advance. The year was a critical one in Viking history, for Sveinn Tjúguskegg (‘Forkbeard’), king of Denmark, completed the conquest of England and had himself declared king late in 1013, only to die five weeks later and allow the English under Ethelred ‘the Unready’ to reclaim the throne. Sigtrygg summoned Norsemen from as far north as the Orkney Islands and as far south as Brittany in the hope that Ireland too could be conquered as a Viking kingdom. This explains the long list of ‘foreign’ Vikings in the Irish annals, and the fact, generally agreed in most accounts, that at the early morning high tide on 23 April 1014, a fleet of Viking ships disgorged their eager warriors onto the Irish coast between the River Tolka and the Howth Peninsula at Clontarf, a few miles north of Dublin.

An engraving by Henry Warren (1794–1879) shows the death of the elderly Brian Boru at the hand of Brodar the Dane during the Battle of Clontarf in 1014.

It was here that a large contingent from overseas, together with men from Leinster and the Dublin Vikings, though not their king, gathered to do battle with Brian’s forces, who had been raiding the surrounding area to squeeze money and food out of the local Christian communities. The only extensive account of the battle comes from the Cocad Gáedel re Gallaib (The War of the Irish with the Foreigners), but it is light on detail. Both sides fought in much the same way, with shield walls to protect the fighting men, and dependence on sheer brute force and savagery. Hardly impartial, the Cocad describes the Viking forces as possessing arrows that were ‘terrible, piercing, fatal, murderous, poisoned’, steeped in the blood of ‘dragons and toads’, while Brian’s Irish wielded swords that were ‘glittering, flashing, brilliant, handsome, straight’. There was, in truth, little difference in the weaponry available to both sides; the difference may well have come in the numbers fielded, but the size of the two armies is simply guesswork.

The rebels were probably drawn up as the annals describe, with the Vikings who had come from overseas in the front, including warriors and commanders from York, the Orkney Islands, the western Scottish coast and the Isle of Man, backed up by the Irish Vikings and finally with the men of Leinster in the rear. The medieval account has Brian’s son, Murchad, leading the men of Munster into the fray, to die in the attempt, supported by some mercenary Norsemen, while the men of Mide under Máel Sechnaill and a reserve from Munster held the rear. But the battle was almost certainly a confused, blood-soaked mêlée as each side endeavoured to encircle and slaughter the other. The clash of mail and armour, the roars and cries of the fighting men and the dying, and the growing mound of gore on the battlefield can be imagined without much difficulty.After a dozen hours of exhausting combat, Brian’s army won the day. The Viking invaders found that their ships had been dispersed as the tide went out. By the time the battle ended, the tide was high again (a fact confirmed by more modern calculations), cutting off any retreat along the coast.

They were pushed back into the sea where, it is to be presumed, many drowned. How many died will never be known, but at the end of a fight in which both sides suffered heavy losses, it is unlikely that quarter was ever considered.When the fog of battle cleared it was found that Brian’s son Murchad and his teenage grandson Tairdelbach had both been killed, Murchard with his legendary twin swords, hewing Vikings left and right, until one of them disemboweled him with a knife.

The principal victim of the battle was Brian Bóruma himself. A man of seventy-three by the time of Clontarf (some annals have him in his eighties), he sat in a tent praying while the battle went on. A band of Danes, wandering from the fight, came across his tent and, according to the Cocad, Brian was killed with an axe through his head, though not before he had cut off his attacker’s left leg and right foot. Brian’s death did not alter the outcome. Sigtrygg remained in Dublin, but his brief ambition to use the arrival of a large fleet of Viking invaders to secure dominance of Ireland, a menace to Irish independence much greater than the threat of a local rebellion, was eliminated in the aftermath of Clontarf and its legendary defence of a fractious Irish liberty.