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Ua Briain, Muirchertach [Murtagh O'Brien]locked

(c. 1050–1119)
  • Damian Bracken

Ua Briain, Muirchertach [Murtagh O'Brien] (c. 1050–1119), king of Munster and high-king of Ireland, was of the Dál Cais dynasty of north Munster and was the son of Toirdelbach Ua Briain (1009–1086) and Derbfhorgaill (d. 1098), daughter of Tadc Mac Gilla Pádraig, king of Osraige. According to the uncorroborated statement of the annals of Ulster, he was born in 1050. Like his great-grandfather Brian Bóruma, Muirchertach tried to make the idea of the high-kingship of Ireland a political reality. He secured his position in the south, and extended Uí Briain control into the midlands and Connacht for a time, but failed to bring to heel Domnall Ua Lochlainn, king of Cenél nEógain in the north. His control of Dublin, his activities in the Irish Sea region, and his courtship of Armagh's clerics all played a part, and he also made use of propaganda: the Cogad Gáedel re Gallaib (‘War of the Irish with the foreigners’) presented Brian Bóruma as the nation's defence against the viking onslaught and Muirchertach as his worthy successor. The national extent of his aspirations is seen in his ruthless treatment of weaker kingdoms and his dealings with the church. He presided over the early formal stages of ecclesiastical reform and the attempt to create a national, diocesan institution.

Muirchertach Ua Briain and his family

As the eleventh century progressed and competition among the major dynasties intensified, the Norse towns became increasingly important in the struggle for power. Toirdelbach Ua Briain made Limerick in the west his capital and in 1075 appointed Muirchertach ruler of Dublin in the east. But when Toirdelbach sent his forces north under Muirchertach, they suffered defeat at Ard Monainn. Toirdelbach realized that a more cautious approach was required. A master of the policy of divide and rule, he tried to keep the Cenél nEógain in check by supporting their rivals, the Ulaid. This had some success, but the events of 1084 showed Muirchertach that it would not do as a long-term strategy.

In that year Muirchertach defeated Donnchad Ua Ruairc of Connacht at the battle of Móin Cruinneoige. Among the casualties on Ua Ruairc's side was Cennétig Ua Briain whose grandfather, Donnchad mac Briain, had been ousted from the kingship of Munster by Toirdelbach. Cennétig, as Toirdelbach's bitter opponent, was appointed king of Telach Óc by the Cenél nEógain in response to Toirdelbach's support for the Ulaid. His fighting on behalf of Ua Ruairc was an ominous sign, for it indicated that Domnall Ua Lochlainn, king of Cenél nEógain, had reached an understanding with Ua Ruairc. The capable Domnall was a problem with which Muirchertach would have to deal directly.

This was forcefully brought home to Muirchertach Ua Briain after his father's death in 1086. Munster was divided between three of Toirdelbach's sons: Muirchertach, Tadc, and their half-brother Diarmait. Tadc outlived his father by a month, but despite being given control over Waterford and its hinterland, Diarmait continued to cause trouble for Muirchertach, who was trying to establish himself in the south. He defeated Donnchad, king of Leinster, in 1087 but two naval expeditions against Connacht failed. Domnall Ua Lochlainn reacted quickly. The alliance with Connacht materialized and the combined forces marched into north Munster, destroying Kincora, the Uí Briain stronghold. Muirchertach was preoccupied with events in the east where Munster dominance had declined since the death of Toirdelbach. A fleet sent to settle his score with Connacht was trapped by Ruaidrí Ua Conchobair, king of Connacht, and Domnall Ua Maíl Shechnaill, king of Meath, who together marched into north Munster. This was the second major attack into the Uí Briain heartland in two years. Muirchertach had no choice but to agree to peace terms with Domnall Ua Lochlainn.

The struggle for the high-kingship

In 1092 Ruaidrí Ua Conchobair was blinded by the Uí Flaithbertaig. This was a major development. Muirchertach Ua Briain moved decisively and attacked Connacht, expelling the Uí Chonchobair, and appointing a puppet king. With Connacht under Muirchertach's control and ruled by an appointee with no traditional rights, the king of Meath recognized that the political map was being redrawn in Muirchertach's favour and submitted to him.

These signs of Ua Briain's growing power caused alarm in the north. The inevitable confrontation between Domnall Ua Lochlainn and Muirchertach occurred at Dublin in 1094. Domnall, supported by the Ulaid, by Ua Maíl Shechnaill of Meath, and by a fleet of ninety ships supplied by Godred (or Gofraid), Norse king of Dublin and the Isles (that is, Man and the islands off the west Scottish coast), routed the Munster forces. However the Ulaid—one-time allies of the Uí Briain—remembered their old loyalties and Domnall's alliance dissolved. Muirchertach then took measures against Dublin and Meath. He expelled Meath's rulers and, to ensure future compliance, divided the kingdom and appointed two puppet kings. This was a highly significant development. Meath was an ancient kingdom, but Muirchertach's casual disdain revealed a new attitude to kingship. No matter how venerable their titles, the rights of lesser kings were to be subordinated to the ambitions of the dominant dynasties in competition for the kingship of all Ireland. Godred was banished from Dublin and died in 1095. Bereft of their leader, the nobles of the Isles dispatched an embassy to Muirchertach requesting a regent to serve for Godred's son's minority. Dublin led the Munster kings deep into the politics of the Irish Sea province and this request is the measure of their success in establishing overlordship here. Muirchertach sent Domnall, son of his brother Tadc, to Dublin: Domnall's mother was the daughter of the former Norse king of Man, Echmarcach Mac Ragnaill, who accompanied Donnchad mac Briain, Muirchertach's great-uncle, on his pilgrimage to Rome in 1064. Muirchertach then asserted his authority over Connacht in the west by expelling the dynasty to which the Uí Chonchobair belonged and set up Domnall Ua Ruairc as king. The high point of Muirchertach's career followed these successes. The Munster king who could force acknowledgement of his supremacy in the north would be rewarded with recognition as king of all Ireland. Control of the eastern seaboard and Irish Sea trade would bring rewards of a material nature. Muirchertach redoubled his efforts against Domnall Ua Lochlainn in the north. However, in the east, his growing power caused the king of Norway, Magnus Barelegs, to be anxious about his interests in the region and he arrived in 1098 to defend them.

The hostility between Muirchertach Ua Briain and Domnall Ua Lochlainn entered a new phase with Muirchertach on the offensive. He led his army north in 1097 but, as happened repeatedly in later attacks, the abbot of Armagh intervened. In 1101 Muirchertach assembled an army from Munster, Leinster, Connacht, Meath, and Osraige and boldly asserted his supremacy by destroying Ailech, the Cenél nEógain capital, and returning along the Slige Midluachra, the ancient route from Ulster to Tara. However, he failed to force Domnall into submission. Magnus of Norway reappeared on a second expedition in 1102. His arrival on the Isle of Man and his designs on Dublin brought him too close for Munster comfort. But Magnus realized that if he were to make gains in Ireland, there were easier pickings in the north. He reached some understanding with Muirchertach, symbolized by the marriage of his son, Sigurd, to Muirchertach's daughter, and both Muirchertach and Magnus launched co-ordinated campaigns northward in 1103.

Muirchertach's and Domnall's forces faced each other for a week when Muirchertach imprudently split his army, sending one contingent south, while he himself with another harried the surrounding territories, perhaps in an attempt to draw out Domnall. In his absence, Domnall decisively defeated the remaining contingent in the battle of Mag Coba, on 5 August. Magnus was killed in a separate skirmish with the Ulaid. These campaigns of the early twelfth century were the closest Muirchertach would come to achieving his ambition of imposing his authority on the whole of Ireland.

Foreign and ecclesiastical engagements

As part of their development of the notion of imperium, kings of England laid claim to Dublin and, by extension, to much of Ireland. Control of Dublin led the Munster kings in the opposite direction and Muirchertach Ua Briain was drawn deep into Welsh politics. A succession of Welsh rulers, including Rhys ap Tewdwr, king of Deheubarth, his son Gruffudd (who remained under Muirchertach's protection in Ireland until c.1115), Cadwgan ap Bleddyn, king of Powys, and his son Owain, sought Munster support and, in difficult times, refuge in Ireland. Gruffudd ap Cynan was born in Dublin and left in 1075 when Muirchertach ruled it. He gained control of Gwynedd with the help of a Waterford fleet. Among the Norman invaders against whom the Welsh sought Munster help was Robert de Bellême, earl of Shrewsbury. By 1102 Robert was gathering support for his challenge to Henry I. He sent Gerald of Windsor to Ireland to seek Muirchertach's assistance. The agreement was formalized with the marriage of Robert's brother, Arnulf de Montgomery, to another of Muirchertach's daughters. A letter survives from Muirchertach to Archbishop Anselm of Canterbury, thanking him for intervening with Henry on behalf of his son-in-law after Robert's failure.

This period also saw the attempt to reorganize the church. Muirchertach presided over the synods of Cashel (1101) and Ráith Bressail (1111). Important measures were adopted at Cashel to free the church from secular control. As a token of support, Muirchertach gave the Rock of Cashel, a site of great symbolic significance, to the church. His motives have been long debated. Cashel was associated with the Eóganachta, the dynasty ousted by the Uí Briain. In handing over Cashel Muirchertach was neutralizing its political associations. However, at a time when a diocesan church was emerging, the grant was a shrewd move if Muirchertach wanted an ecclesiastical office of first importance situated in his territories. His generosity paid dividends, for the Synod of Ráith Bressail legislated for the creation of a diocesan organization, with metropolitan sees at Armagh and Cashel. Muirchertach took an active role in important ecclesiastical appointments, seeing to the promotion of men of proven ability and reforming zeal like Bishop Domnall Ua hÉnna of Killaloe and Máel Muire Ua Dúnáin, 'preeminent bishop in Munster'. He was probably involved in the selection of Donngus (Donatus) Ua hAingli and Samuel Ua hAingli as bishops of Dublin and his name appears on the letter to Anselm requesting the consecration of Máel Ísa (Malchus) Ua hAinmire as first bishop of Waterford in 1096. After 1111 Máel Ísa became the first archbishop of Cashel. Muirchertach was also behind the appointment of Gilla Espaig (Gilbertus) as first bishop of Limerick and had a hand in the consecration in Munster of Cellach (Celsus) Mac Áeda as bishop of Armagh in 1106.

Death and achievement

Muirchertach Ua Briain's advance suffered a rude check after he fell gravely ill in 1114. Domnall Ua Lochlainn and Toirdelbach Ua Conchobair of Connacht mustered a great army and defeated the Munstermen. However, the allies quarrelled, and Domnall had no choice but to treat for a year's truce. Muirchertach faced an internal challenge from his own half-brother Diarmait, who deposed him. He recovered somewhat the following year and imprisoned Diarmait in Limerick, before marching into Leinster and then into Meath. In 1118—the year Diarmait died in Cork—Ua Conchobair led his army into Munster. He applied Muirchertach's device for dealing with troublesome kingdoms to Munster and divided Munster between Tadc Mac Carthaigh and Diarmait's sons. Muirchertach's sons (at least one of whom, Domnall, was born of his father's union with Derbfhorgaill, daughter of Ua Laidcnen, king of Airgialla) were thereby excluded from the kingship. Muirchertach, who entered the monastery of Lismore, Waterford, as a penitent in 1116, died in March 1119 (the sources give variously the 8th, the 10th, and the 12th) and was buried at Killaloe, Clare.

The reign of Muirchertach Ua Briain marked the apogee of Uí Briain influence in Munster, and of Munster dominance in Ireland. He was one of the first Irish kings to make his power felt outside Ireland, in the Irish Sea region, Wales, and western Scotland: King Edgar of Scotland was moved to send him the tribute of 'a camel, a beast of wondrous size' (annals of Inisfallen, s.a. 1105). He played a vital role in the creation of the national institution of the church, and in his correspondence Anselm of Canterbury referred to him as king of Ireland. A similar ambition with regard to the institution of kingship guided his actions in expelling weaker dynasties, dividing their kingdoms, and promoting puppet kings. Indeed, the complex web of alliance and counter-alliance that characterized the politics of his time is symptomatic not of a state of anarchy, but of the trauma that precedes the emergence of a new order.


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