Events from the 11th century in Ireland.
11th century in Ireland
|10th century | 11th century | 12th century|
- Máel Sechnaill mac Domnaill, without a battle, yields to Brian Boru, King of Munster who, effectively becomes King of Ireland and reigns until his death in 1014.
- Brian Boru makes an expedition to the north to take hostages from the northern states.
- Brian Boru makes a second expedition to the north to take hostages from the northern states: during this expedition, he visited Armagh, making an offering of twenty ounces of gold to the church and confirming to the apostolic see of Saint Patrick, ecclesiastical supremacy over the whole of Ireland (as recorded in the Book of Armagh).
- Death of Mael Ruanaidh Ua Dubhda, King of Uí Fiachrach Muaidhe.
- Brian Boru makes a triumphal progress around Leath Cuinn, taking hostages from every northern state, thus demonstrating he was undisputed King of Ireland.
- Death of Cú Connacht mac Dundach.
- Brian Boru campaigned against the Vikings of Dublin under their King Sigtrygg Silkbeard and North Leinster led by Máel Mórda Mac Murchada, following attacks by them on Brian's ally Máel Sechnaill mac Domnaill.
- 23 April: Battle of Clontarf, at which the Vikings and men of North Leinster are defeated by Brian Boru, who is killed in the battle as is Máel Mórda mac Murchada.
- Death of Cass Midhe, Irish lawyer
- Niall mac Eochada defeats the Dublin Norse at sea.
- Death of Mael Seachnaill II, Overking of the Uí Néill, who had reigned since 980, and who became King of Ireland on the death of Brian Boru in 1014 and ruled until his death.
- 1024 and 1026
- Niall mac Eochada invades Dublin and take hostages.
- Death of Gormflaith (b. 960), daughter of Murchad mac Find, King of Leinster, and third wife of Brian Ború.
- Ragnall ua Ímair, King of Waterford slain by Sigtrygg Silkbeard.
- Sigtrygg Silkbeard driven out of Dublin by Echmarcach mac Ragnaill.
- Death of Sigtrygg Silkbeard.
- Ímar mac Arailt was expelled from Dublin by Echmarcach mac Ragnaill, who then reigns as king.
- Echmarcach mac Ragnaill, King of Dublin is expelled from the town.
- 30 April: A tornado hits Ros-deala (in modern County Westmeath)
- Death of Diarmait mac Mail na mBo, a king of Leinster and a contender for the title of High King of Ireland. He was one of the most important and significant Kings in Ireland in the pre-Norman era.
- In a campaign against the Uí Néill and their allies in the north, Muirchertach Ua Briain (son of Toirdelbach) is defeated by the Airgíalla near Áth Fhirdia (modern Ardee, County Louth) with heavy loss.
- Birth of Saint Ceallach (Celsus), (d 1129), future abbot of Armagh. He will preside at the synod of Rathbreasail in 1111.
- Gruffudd ap Cynan, Irish-born claimant to the Kingdom of Gwynedd, sails from Waterford to St David's with an army of Hiberno-Normans to enforce his claim.
- Muirchertach Ua Briain becomes King of Munster and claimant to the Kingship of Ireland, and reigns until 1119.
- Death of Madudan Reamhar Ua Madadhan, Chief of Síol Anmchadha
- Birth of Saint Malachy (Middle Irish: Máel Máedóc Ua Morgair; Modern Irish: Maelmhaedhoc Ó Morgair)
- Moody, T. W.; Martin, F. X., eds. (1967). The Course of Irish History. Cork: Mercier Press. p. 104.
- Duffy, Seán (2005). The Concise History of Ireland. Dublin: Gill & Macmillan.
- Moody, T. W.; Martin, F. X., eds. (1967). The Course of Irish History. Cork: Mercier Press. p. 113.
- Annals of Ulster.
- Moody, T. W.; Martin, F. X., eds. (1967). The Course of Irish History. Cork: Mercier Press. p. 114.
- Mac Annaidh, S., ed. (2001). Illustrated Dictionary of Irish History. Dublin: Gill and Macmillan.
- Benjamin T. Hudson, ‘Niall mac Eochada (d. 1063)’, Oxford Dictionary of National Biography, Oxford University Press, 2004 accessed 18 April 2008
- Heald, Henrietta (1992). Chronicle of Britain. Jacques Legrand. p. 172. ISBN 0-19-211695-9.
- Moody, TW; Martin, FX, eds. (1967). The Course of Irish History. Cork, Ireland: The Mercier Press. p. 115.
- Moody, TW; Martin, FX, eds. (1967). The Course of Irish History. Cork, Ireland: The Mercier Press. p. 122.
- Annals of Ulster.
- Annals of Inisfallen.
- The Welsh Academy. Encyclopaedia of Wales.
- Foster, R. F., ed. (1989). The Oxford Illustrated History of Ireland. Oxford University Press. ISBN 0198229704.
- Moody, TW; Martin, FX, eds. (1967). The Course of Irish History. Cork, Ireland: The Mercier Press. p. 118.