The Battle of Clontarf, fought on Good Friday in 1014 AD, is one of the most famous events in Irish history.
After the re-establishment of Dublin in 917 and its development into a wealthy town, control of Dublin became a necessity for any king seeking control over all of Ireland.
In the late tenth century the Dál Cais rose to power in Munster. Their most noteworthy king was Brian Bórama. At the turn of the eleventh century, the Norse of Dublin became involved in conflicts between Brian Bórama and the king of Leinster, Mael Morda. There were a number of serious battles in 1012, and 1013 was marked by continuous warfare. Brian, his son Murchad and Maelsechnaill II of Meath plundered Leinster, but did not succeed in their attempt to take control of Dublin.
1014 began with the Dublin Norse assembling allies from the western and northern Isles of Scotland and the Isle of Man. The ensuing battle took place at Clontarf on Good Friday in April of that year. Eventually the Leinstermen and their Norse supporters were defeated, but both sides suffered heavy casualties. Both Brian Bórama and Mael Morda were killed.
The end of the Viking era
The battle of Clontarf is often interpreted as a major defeat for the Vikings and one which changed their fortune in Europe. Certainly, the Vikings suffered great losses, and the overthrow seems to have made an impression on their saga writers, who spoke of omens before the battle, such as boiling blood raining down on the warriors.
The Battle of Clontarf was primarily a conflict between Munster and Leinster. Its outcome was less damaging to the power of the Norse of Dublin than to Munster, who did not recover for over a decade. The position of the Munstermen in Ireland was open to continuous challenge until they were overthrown by the O’Connors of Connacht and the Mac Lochlanns of Ulster a century later. Dublin's strategic position and wealth, including its powerful fleet, ensured that it was of paramount importance to those attempting to rule Ireland and between 1014 and 1170 almost all of its rulers were outsiders imposed by one or other of the kings of Connacht, Munster, Ulster and Leinster.
In the 1160s Dublin came under the dominance of Diarmuid Mac Murchadha, king of Leinster, until he was deposed by Ruaidhri Ua Concobhair in 1166. Mac Murchadha left to seek help from England, and this eventually led to the arrival of Strongbow and the capture of Dublin by the Anglo-Normans in 1170.
Maeve Sikora, National Museum of Ireland