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Battle of Clontarf 23rd April 1014

Protagonists: Brian Boru, High King of Ireland against Sigtrygg Silkbeard, King of Dublin and Mael Morda, King of Leinster.

Outcome: Victory for Brian Boru.

Many myths have grown up surrounding the battle of Clontarf not least of which is that it was a battle between the Irish and Viking invaders resulting in the expulsion of the Vikings from Ireland. The truth is far more complex. There were Irish and Vikings fighting on both sides, Sigtrygg’s own brother fought for Brian Boru. Some reports even place English, Welsh, Scottish, Norman, Flemish and French mercenaries at the battle. The Viking forces that fought on both sides did not just come from Ireland they came from all over the Viking world, Orkney, Iceland, Isle of Man, Norway and Denmark. Sygtrygg remained King of Dublin until his death in 1042.

Regardless of where the various contingents came from the battle was one of the bloodiest in Irish history. The two armies were fairly evenly matched in numbers 7000 – 8000 each. By the end of the day 7500 – 10,000 lay dead (1600 – 4000 of Brian Boru’s army including himself and around 6000 from the Viking/Leinster alliance).


Almost every leader on both sides died resulting in Ireland sliding back into a state of petty feuding between local kings and chieftains.

The bulk of Brian Boru’s army was made of the clans of Meath under Máel Sechnaill, clans from Connacht, Munster as well as Boru’s own clan of Dal Caissan. There was also a force of over 1000 Viking mercenaries, including a contingent from the Isle of Man and Scotland as well as Ireland.

The Viking/Leinster army consisted of the clans of Leinster under Mael Morda, Dublin Vikings, Orkney Vikings under Sigurd, Earl of Orkney (himself half Irish) and  Manx (Isle of Man) Vikings under Brodir.

The battle

The night before the battle the Viking forces from Orkney and the Isle of Man sailed out of Dublin in an attempt to make Brian Boru think that they were leaving, whereas in actual fact once out of sight of land they turned back and landed on the beach at Clontarf about a mile and a half from the walls of Dublin. At this time Dublin was situated on the south bank of the River Liffey.

The armies were drawn up as follows:

Brian Boru’s Irish alliance right to left: 1000 Viking mercenaries, 1500 Connacht clansmen, 2000 Munster clansmen, 1400 Dal Caisson clansmen while 1500 Meath clansmen were held some considerable way back behind the right wing on the orders of Máel Sechnaill who had had a disagreement with Brian Boru and was perhaps waiting to see which way the battle would go.

Sygtrygg’s Viking/Leinster alliance left to right: 1000 Dublin Vikings (a further 1000 stayed in Dublin along with Sygtrygg), 3000 Leinster clansmen, 1000 Orkney Vikings, 1000 Manx Vikings on the beach near where the longboats had been beached.

As the two armies closed on each other a number of personal duels were fought between various chieftains as was usual. Eventually the armies came together. Brodir leading his Manx Vikings against the Dal Caisson clansmen fought his way through several ranks and was only stopped by Wolf the Quarrelsome who knocked him to the ground twice. Brodir was only able avoid being killed by running off into some nearby woods. At this point Murchad (Brian Boru’s son) led a charge at the Manx Vikings, who with their leader hiding in the woods were eventually broken and began to flee back to their ships.

Sigurd, Earl of Orkney, had brought a raven banner with him to the battle which would bring victory to the army that followed it and death to anyone who carried it. After several warriors carrying it had been killed Sigurd was forced to pick up the banner himself only to be struck down and killed by Murchad.
The Dublin Vikings had been fighting the Viking mercenaries of Brian Boru and were slowly forced back. As a result of this the clansmen of Leinster in the centre found themselves isolated. Some of them joined the Manx and Orkney Vikings who were now trying to get back to their longboats, which due to the rising tide were now cut off and many of them were drowned.

At this point Máel Sechnaill saw that the battle was turning and led his Meath clansmen against the Dublin Vikings who were trying to get back to their fortress in Dublin breaking them completely and killing most of them.

It was at this late stage that Brodir noticed from his hiding place in the woods that Brian Boru was in a tent nearby (he had not wanted to fight himself as it was Good Friday and he would not fight on a fast day) and only lightly guarded. Brodir and a few men with him attcked and quickly killed the guards and Brian Boru himself. Wolf the Quarrelsome saw what had happened and was able to capture Brodir and his men. Brodir’s men were promptly executed while Brodir was given a very slow lingering death for the cowardly way in which he had killed Brian Boru.

The aftermath

With the exception of Sygtrygg who did not take part in the battle every leader in the allied Viking army was killed including  Mael Morda and most of his chieftains. Apart from Brian Boru most of his sons were also killed leaving no effective heir to succeed him. Máel Sechnaill reclaimed the High Kingship of Ireland which Brian Boru had forced him to give up but he was unable to act effectively.

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