Donnell Mór O'Brien, King of Munster

How are you related to Donnell Mór O'Brien, King of Munster?

Connect to the World Family Tree to find out

Donnell Mór O'Brien, King of Munster's Geni Profile

Share your family tree and photos with the people you know and love

  • Build your family tree online
  • Share photos and videos
  • Smart Matching™ technology
  • Free!

Donnell Mór O'Brien, King of Munster

Gaelic: Domnall Mór mac Toirrdelbaig Ó Briain, King of Munster
Birthplace: Connaught, Ireland
Death: 1194 (34-43)
Place of Burial: Limerick, Ireland
Immediate Family:

Son of Torlough O'Brien, King of Thomond and Raghnait, daughter of the Ua Fogartaigh Raghnait O'Fogarty
Husband of Urlachan MacMurrough
Father of Mor O'Brien, Lady of Connacht; Donough Cairbreach O'Brien, Lord of Thomond and Duncola O'Ceallaig - 25
Half brother of Muirchertach au Briain

Occupation: King of Munster, King of Leinster
Managed by: Private User
Last Updated:

About Donnell Mór O'Brien, King of Munster

Domnall Mor was the son of Tairdelbhach O'Brien, King of Munster (1142-1167), and the great-great-great grandson of Brian Boru. He established Holy Cross Abbey in 1180 and Kilcooley Abbey in 1184.

Domnall Mor O'Brien

From Wikipedia, the free encyclopedia

Domnall Mor mac Turlough O'Brien (Irish: Dómhnaill Mór mac Toirrdelbach ua Briain) was king of Munster and king of Thomond in Ireland from 1168 to 1194.


Domnall Mor ("Domnall the Great") was the third son of Turlough mac Dermot, the king of Munster from 1142 to 1167. He ascended to the throne in 1168 after the death of his eldest brother Muirchertach mac Turlough, king of Munster and Desmond from 1167 to 1168. Muirchertach was killed at the instigation of his cousin Conchobar mac Muirchertach O'Brien. His other brother Brian of Slieve Bloom was blinded in 1169. The same year, Domnall entered into conflict with Erenn Ruaidri O'Conchobar and was forced to pay him a tribute of 300 cows.

In 1171, he submitted himself to Henry II, king of England, at Cashel, but he continued to fight successfully against the Normans and their incursion into southwest Ireland for many years. In 1175, having demolished the Normans at the Battle of Thurles in Tipperary, he consolidated his power by blinding two of his cousins, Dermot mac Taig O'Brien and Mathgamain mac Toirdhelbeach O'Brien, in Limerick. He was, however, driven from Thomond by Erenn Ruaidri the same year. In 1176, he drove out the Normans from Limerick, and in 1185 when Prince John of England intervened in Ireland, Domnall Mor demolished them again when John was plundering along the Suir River. The same year he also blinded the last Dermot brother. In 1184, part of his lands were enfeofed to Philip de Braose, Lord Deputy of Ireland. In 1188, he helped the men of Connacht under Conchobar O'Conchobar to overcome Jean de Courcy in the Curlew Mountains. In 1193, the Normans devastated Clare in reprisal and plundered Domnall's possessions in Ossory.

He established the Holy Cross Abbey in 1180 and Kilcooly Abbey in 1184, both under the Cistercian Rite.[1]

According to the Annals of Ulster, he was the last king of Munster, dying in 1194.


Domnall Mor married Orlacan, daughter of Dermot mac Murrough. He left several sons who fought amongst themselves and with their cousin Muichertach, son of Brian of Slieve Bloom, for the succession in Thomond.

   * Muirchertach Finn (King of Thomond 1194-1198, restored 1202 or 1203-1208 or 1210, blinded 1208 or 1210, died 1239)

* Conchobar Ruadh (King of Thomond 1198-1202 or 1203, killed 1202 or 1203)
* Donnchadh Cairprech (King of Thomond 1208 or 1210-1242)

  1. ^ Archdiocese of Cashel Website.

Domnall Mór

King of Thomond & Munster


"The Annals of Tigernach provide an interesting insight into Domnall Mór’s growth to power after the death of his father Toirdelbach. Under the year 1168, there are two entries which distinguish between two particular titles. Firstly Domnall Ó Briain is said to have taken ríge Tuadmuman or the kingship of north Munster (the literal meaning of Thomond) while his brother Brain took the kingship of Urmuman (Ormond – or east Munster). The next entry states that Brian was taken as prisoner by his brother who then acquired ríge Dál Cais uile – the kingship of the whole of the Dál Cais."

view all

Donnell Mór O'Brien, King of Munster's Timeline

Connaught, Ireland
Connaught, Ireland
Thomond,North Munster,Clare,Ireland
Age 39
Saint Mary's Cathedral, Limerick, Ireland