Gaelic-Irish vs Norse-Gaels in The Battle of Clontarf

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The Battle of Clontarf was a battle which took place in 1014 AD at Clontarf on the coast of Ireland between the forces of the High King of Ireland and a Norse-Irish alliance.

When the Viking Age began, Norsemen began carrying out raids on the Gaelic Irish in the late eighth century.  These raids continued over the following decades and the Vikings had founded a number of settlements along the Irish coast.  By 838 AD, these Vikings had firmly established themselves in Dublin when they built a fortified longphort.

A longphort (plural longphuirt) is a term used in Ireland for a Viking ship enclosure or shore fortress.

By the tenth century, “Viking Dublin” had then developed into the Kingdom of Dublin, becoming a thriving town with a large area of the surrounding countryside.  These Viking-Dublin rulers also controlled extensive territories in the Irish Sea, reaching all the way to York (Jorvik) in Northumbria at one time. Over time, many of these Vikings were assimilated into Gaelic society and became the Norse-Gaels.

The Norse-Gaels (Old Irish: Gall-Goídil, Irish: Gall-Ghaedheil or Gall-Ghaeil, Scottish Gaelic: Gall-Ghàidheil, meaning “foreigner Gaels”) were a people of mixed Gaelic and Norse ancestry and culture.

Gaia, which visited Dublin in July 2005, is an exact replica of the 1000-year-old Gokstad, excavated in Norway in 1880 and said to contain the remains of Olav Geirstadalv, the first Viking king of Dublin. (Vestfold Fylkeskommune)

Some background leading to the Battle of Clontarf

In the tenth century, the Gaelic Irish tribe Dál gCais (Dalcassians) began to expand. By the time of his death in 951, Cennétig mac Lorcáin (father of Brian Boru) had become King of Tuadmumu (later known as Thomond).  His son, Mathgamain mac Cennétig, was King of Munster when he died 25 years later in 976.
Upon his death, Mathgamain’s brother, Brian Boru, quickly asserted his claim to the kingship of Munster and then invaded the Kingdom of Leinster (territory marked orange on map below) and gained its submission.

Brian Boru (Old Irish: Brian Bóruma mac Cennétig; modern Irish: Brian Bóramha)

This was the beginning of the rise of the Brian Boru, who would eventually become the High King of Ireland.

Ireland 950 AD, Map by

Tensions between the Norse Gaels and Irish Gaels continued as they attacked each other seeking dominance over the other’s regions.  In the year 980 AD, the Norse-Gaels of Dublin led by Amlaíb Cuarán (Old Norse: Óláfr Sigtryggsson or Óláfr kváran) were defeated by the Gaelic Irish of Meath who were led by Máel Sechnaill mac Domnaill at the Battle of Tara (near the Hill of Tara in Ireland).

The Irish-Gaels faced Amlaíb’s sons—Amlaíb himself was by now an old man

The battle was a devastating defeat for the Viking Norse Gaels and led to the Irish Gaels regaining control over the Kingdom of Dublin.

Máel Sechnaill occupied the city and imposed a heavy tribute on the citizens. 

In the aftermath of this defeat Amlaíb Cuarán abdicated (or was removed from power) and was replaced by Glúniairn (Járnkné), a half-brother of adversaries Máel Sechnaill and Sigtrygg Silkbeard (paternal).

By 989 Ad, Sigtrygg Silkbeard succeeded his paternal half-brother Glúniairn as King of Dublin.

The Irish annals record little information about the specifics of how Sigtrygg Silkbeard gained power or of Dublin during the first five years of his reign.  Although it may have been because of the arrival of the future King of Norway, Olaf Tryggvason who took up residence in Dublin for a few years after marrying Sigtrygg’s sister Gytha.  Olaf Tryggvason had met Gytha while raiding along the coasts of the Irish Sea.  The presence of a powerful Viking leader in Dublin was a deterrent to Irish raids and Trygvason may have weakened Sigtrygg’s foes by plundering them.

In the year 995 AD, the Sigtrygg Silkbeard and his nephew, Muirchertach Ua Congalaich, attacked the Christian church at Donaghpatrick in County Meath.

In retaliation, Máel Sechnaill entered Dublin and took the Ring of Thor and the Sword of Carlus

Raids and battles between Brian Boru and Máel Sechnaill over the region persisted until in 997 AD when they met in Clonfert and reached an agreement recognizing each other’s reign over their respective halves of the country.

  – Máel Sechnaill in the north.
  – Brian Boru in the south.

But this peace was very short-lived and in the following year Brian Boru attacked the Uí Néill stronghold of Meath.
Máel Sechnaill in turn responded by attacking Munster.

Again, this went back and forth until in the year 998 AD, Máel Sechnaill temporarily united with Brian Boru and forced Sigtrygg to recognize their lordship by giving hostages.

Brian Boru and Máel Sechnaill returned to their struggle of trying to dominate each other and the other kingdoms of Ireland.  Sigtrygg took advantage of the two kingdoms breaking their truce and had allied himself with his uncle Máel Mórda, the King of Leinster. Together they met Máel Sechnaill and Brian Boru at the Battle of Glenmama in 999 AD.

However, the Norse Gaels were again defeated.

Meath about the year 900 AD.

Over the following years, Gaelic Irish Máel Sechnaill and Brian Boru continued struggling for supremacy over each other and Ireland.

Brian Boru resumed his attacks on Máel Seachnaill and in 1000 AD, he marched on Tara with the combined armies of Munster, Osraige, Leinster, and Dublin. However, after an advance party consisting of the latter two groups was destroyed by Máel Sechnaill, Brian Boru withdrew from the area without giving battle.

Having rebuilt his force, in 1002 AD Brian Boru again marched with the same army to Athlone with success this time and took the hostages of Connacht and Meath.

Brian Boru had now gained the upper hand over the other kings and began to coordinate his forces on land and at sea to triumph over the other kingdoms.  Some rulers were able to bring the advance of Brian’s land army to a halt, they could not prevent his fleet from attacking the shores of their kingdoms. Once Brian entered the province of Ulster, he had systematically defeated each of the regional rulers who defied him and forced them all to recognize him as their overlord and High King.

Brian Boru had now become the undisputed High King of Ireland.

This did not sit well with the Norse-Gael ingdoms of Dublin and Leinster. They revolted.

Brian Boru continued to consolidate his hold on Ireland by eventually obtaining the submission of the northern territories of Cenél nEógain, Cenél Conaill and Ulaid, following a series of circuits of the northern part of the island.

He secured his hold on Ireland following “a great hosting…by land and sea” into the Uí Néill territory of Cenél Conaill in 1011 AD.

It was not long, however, before fighting was renewed.

Flaithbertach Ua Néill, king of the Cenél nEógain, who would’ve been in line to succeed Ireland’s High-Kingship, resented Brian Boru’s rise to the position of High-King.

He attacked his Cenél Conaill neighbors in 1012 but, while doing so, Máel Seachnaill attacked the Cenél nEógain inauguration site of Tullahoge. Flaithbertach in turn raided Meath the following year and Máel Sechnaill was forced to back down.

Sigtrygg and Máel Mórda took advantage and themselves raided Meath.

Máel Sechnaill sent his army to raid the hinterland north of Dublin as far as Howth but he was defeated. He lost 200 men including his son Flann. Sigtrygg then sent a fleet along the coast to attack the Munster town of Cork, but that was defeated and Sigtrygg’s nephew was killed.

A full-scale conflict was inevitable.

In 1013 Brian led a force from his own province of Munster and from southern Connacht into Leinster; a detachment under his son Murchad ravaged the southern half of the province of Leinster for three months. The forces under Murchad and Brian were reunited on 9 September outside the walls of Dublin. The city was blockaded, but it was the High King’s army that ran out of supplies first, so that Brian was forced to abandon the siege and return to Munster around Christmas.

The Norse-Gael Sigtrygg went overseas in search of Norse support and enlisted the help of Sigurd Hlodvirsson, the Earl of Orkney and Brodir, a warrior of the Isle of Man.

According to the Icelandic Njáls Saga, Sigtrygg promised both men the kingship of Ireland if they defeated Brian Boru.

The Viking fleets of Orkney and Mann sailed into Dublin in Holy Week (the week just before Easter), in the year 1014 AD.  

Brian Boru mustered the army of Munster, which was joined by Máel Sechnaill and two Connacht kings, Mael Ruanaidh Ua hEidhin, king of Uí Fiachrach Aidhne, and Tadhg Ua Cellaigh, king of Uí Maine, and marched on Dublin.

After his arrival at Dublin, Brian Boru sent his forces north across the river to plunder the area known as Fine Gall, and they torched the country as far as Howth.

Brian Boru, now in his 70s, did not go with them but stayed behind to pray.

The Dublin forces set out by land and were joined in Clontarf at high tide by the Viking fleet that was in Dublin Bay.

The front line of the Dublin/Leinster forces were the “foreign Vikings” (Norse-Gaels), led by Brodir, Sigurd and a man called Plait, described as “the bravest knight of all the foreigners“.

Behind them were the men of Dublin, commanded by Dubgall mac Amlaíb and Gilla Ciaráin mac Glún Iairn. Behind them again came the Leinstermen, headed by Máel Mórda.

Sigtrygg remained in Dublin with enough men to defend it, should the battle go against them. He watched the battle from the walls with his wife Sláine, the daughter of Brian.

Here was the battleline:

  • At the front of Brian’s forces were the Gaelic Irish Dál gCais (Dalcassians), led by Brian’s son Murchad, Murchad’s 15-year-old son Toirdelbach, Brian’s brother Cudulligh and Domnall mac Diarmata of Corcu Baiscind.
  • Behind them were the other forces of Munster, commanded by Mothla mac Domnaill mic Fáeláin, king of the Déisi Muman, and Magnus mac Amchada, king of Uí Liatháin.
  • Next came the Connachta, led by Mael Ruanaidh Ua hEidhin and Tadhg Ua Cellaigh.
  • To one side of them were Brian’s Viking allies; Fergal ua Ruairc, with the Uí Briúin and the Conmhaícne was placed on the left flank.
  • After the Connachta came Máel Sechnaill and the men of Meath, but (the Cogad says) he had made an agreement with the men of Dublin that if he would not attack them, they would not attack him.

The battle opened with Plait taunting Domnall mac Eimin, a Scottish ally of Brian.

The two men marched out into the middle of the field and fought, and both died, “with the sword of each through the heart of the other, and the hair of each in the clenched hand of the other.”

It was after the two men fell that the battle proper got under way.

The battle is described as having been remarkably loud and bloody.

The Irish-Gael men of Connacht fought the Norse-Gael men of Dublin and the fighting was so fierce that only 100 Connachtmen and twenty Dublinmen survived.

The last casualties occurred at “Dubgall’s Bridge”, a bridge over the River Tolka, on the road back to Dublin.  

Brian’s son Murchad, at the head of the Dál gCais army, took on the foreign Vikings and personally killed 100 of the enemy—fifty with the sword in his right hand and fifty with the sword in his left.

The Vikings were better armored and wore chain mail, while the Irish-Gaels did not.  Yet the Irish-Gaels gained the advantage, partly through the use of small spears which they hurled at the enemy and partly through numerical superiority.

1. Clondalkin and Kilmainham were plundered, Brian’s son Donnchad (Donough) sacked Leinster (1014); 2. Brian’s forces began war, camped near Kilmainham; 3. Finegall and Howth were plundered; 4. Vikings left Dublin to engage Brian; 5. Overseas Viking fleet arrived; 6. Battle of Clontarf; 7. Retreat of Vikings, some drowned in the sea, some forced through Dubgall’s Bridge and were attacked again, a few returned to Dublin; 8. Brodar’s possible route, killed Brian and was killed himself; 9. Brian’s remains to Swords, then to Armagh.

The battle, which had begun at first light, lasted all day.

Viking re-enactors from all over the world at the Battle of Clontarf millennium commemoration in Saint Anne’s Park, Dublin (lining up before charging at the opposition). April 19th, 2014.

Eventually, the Norse-Gael forces of Dublin and Leinster broke.

Some withdrew towards their ships, while others made for a nearby wood.
Unfortunately the tide had come in and had cut off passage to the wood.  The tide had also carried off the Viking ships. With no way out, the Norse-Gaels and their Viking allies were killed in large numbers, many of them by drowning.

It was at this point when the Norse-Gaels were fleeing that Brian Boru’s grandson Toirdelbach was killed when he tried to pursue them fleeing into the sea.  He was hit by a wave and thrown up against the weir and drowned.

In the battle, Murchad had killed Sigurd, the earl of Orkney, but shortly afterwards was killed himself.

Brian Boru was in his tent, still praying, when the Viking Brodir found and killed him.

Nineteenth-century engraving of Viking warrior Brodir about to slay Brian Boru while he is kneeling in prayer.

Brodir himself was then killed.

The battle had ended with the Gaelic Irish Máel Sechnaill restored as High King of Ireland where he remained until his death in 1022 AD.

A sculpture of Máel Seachnaill in Trim, Co. Meath, by James McKenna.

Sigtrygg emerged with his kingdom intact and Máel Sechnaill was now recognized as the High King of Ireland. 


 by Njord Kane © 2016 Spangenhelm Publishing

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