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Ireland: Battle of Clontarf



The Battle of Clontarf was occurred during a war between the High King of Ireland and the King of Leinster.


The opposing armies met at Clontarf on Good Friday, April 23, 1014.

Armies & Commanders:

Munster Irish

  • Brian Boru
  • approx. 7,500 men

Leinster Irish & Dublin Vikings

  • Máel Mórda mac Murchada
  • Sigtrygg
  • approx. 7,000 men

Battle of Clontarf Summary:

In the early 1000s, Brian Boru, High King of the Irish, worked to unite all of the provinces of Ireland under his rule. By 1011, he had succeeded in achieving his goal, though several regional rulers submitted with great reluctance. The King of Leinster, Máel Mórda mac Murchada, rose in revolt in 1012. This was not the first time that Máel Mórda had rebelled and Brian moved to quickly destroy Leinster's forces. Campaigning in 1013, Brian's forces marched into Leinster, while his son, Murchad, ravaged the southern part of the province.

Reuniting outside of Dublin, they unsuccessfully laid siege to the city and were forced to withdrawal around Christmas. Realizing that aid would be needed to continue the rebellion, Máel Mórda sent his cousin Sigtrygg Silkbeard, the Viking king of Dublin, to find help overseas. Sailing the Orkneys, he was able to enlist support from the Earl of Orkney, Sigurd Lodvesson. The earl then convinced the leader of the Isle of Man, Brodir, to join the cause. As the Vikings converged on Dublin, Brian raised his army for the 1014 campaign.

As his army neared Dublin, Brian was shocked to have the contingent of men from Meath, led by former High King Máel Sechnaill mac Domnaill, withdraw from his army. Pressing on, they arrived outside the city and set up camp. Within the city, Máel Mórda and Sigtrygg conceived a plan to surprise Brian the next day. Embarking all but a small force under Sigtrygg, Máel Mórda and his Viking allies sailed from the city and landed north of the River Liffey at Clontarf. From this position they were close to the city, but were only able to access it over one bridge across the Liffey.

The next day, Good Friday, Brian awoke and quickly reformed his army to meet the new threat. Aligning his troops, he placed 1,400 Dal Caissans on his left along the beach, with his line extending inland and composed of warriors from Munster and Connacht. On his right, were nearly 1,000 Manx Vikings and other mercenaries. Confronting Brian, Máel Mórda arranged his forces with Sigurd's Vikings in the center and Brodir's men on the right, near their ships. The left was largely composed of men from Leinster and Dublin. With the two lines taunting each other, several champions emerged to fight individual battles.

As these concluded, the two armies clashed with Máel Mórda and his allies gaining an early edge. All along the line, the Vikings achieved success. This led to Brian's army succeeding on their right, while Máel Mórda was able to advance on his right. On the beach, Brodir's men were gaining ground until he encountered Brian's brother, Wolf the Quarrelsome. Engaging in personal combat, Wolf knocked Brodir to the ground, forcing him to flee. In the center, Sigurd was getting the better of the men from Munster until he was struck down attempting to defend his banner.

As the battle raged through the afternoon, Brian's forces gained an upper hand. Pushing Máel Mórda's men back on both flanks, they were able to cut them off from their ships. Seeing the battle as lost, they began fleeing back towards Dublin. As they retreated towards the bridge, Máel Sechnaill led the Meath troops into the battle. Arriving at the bridge first, they cut off Máel Mórda's line of escape. With the enemy trapped, Brian's forces pressed their attack and killed Máel Mórda and the majority of his army.

While, the battle raged, Brian withdrew to his tent to pray. He was spotted by Brodir who, after his defeat by Wolf, had fled into the nearby woods. Gathering a small band of men, Brodir attacked Brian's tent and killed the king and his retainers. Sources indicate that Wolf subsequently tracked down Brodir and killed him in revenge for his brother's death.


The Battle of Clontarf cost Brian Boru between 1,600 to 4,000 dead. In addition to himself, Brian army's suffered the loss of several of his immediate family. Máel Mórda paid for his defeat with his life and those of around 6,000 of his men. Though a victory for Brian and his largely Irish forces, his death, and those of several of his family, led to a power vacuum emerging within Ireland. The battle saw the power of the Vikings broken, but as a result the country soon sank into regionalized warfare between the provinces. Of those who played a role in the revolt, only Sigtrygg escaped with his life and reputation. He continued to rule in Dublin until his death in 1042.

Selected Sources

  1. About.com
  2. Education
  3. Military History
  4. Conflicts & Battles
  5. Battles & Wars: 1001-1200
  6. Overview of the Irish Battle of Clontarf

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