Muircheartach Ua Briain (old spelling: Muirchertach Ua Briain) (c. 1050 – c. 10 March 1119), son of Toirdelbach Ua Briain and great-grandson of Brian Bóruma, was King of Munster and later self declared High King of Ireland.
Contents
[hide]
• 1 Background
• 2 King of Munster
• 3 King of Ireland with opposition
• 4 Alliance with Arnulf de Montgomery
• 5 Magnus Barelegs
• 6 Final years
• 7 Assessments
• 8 Notes
• 9 References
[edit] Background


Major political divisions of Ireland similar to those in Muircheartach's time
Muirchertach was a son of Toirdelbach Ua Briain, a previous Dalcassian king of Ireland. In 1086 his father died and the province of Munster from which he had claimed kingship of Ireland had been split between his three sons: Tadc, Muirchertach and Diarmait. Tadc died soon after, and Muirchertach banished Diarmait from Munster, claiming its kingship for himself.
[edit] King of Munster
Between 1086 and 1101, Muirchertach consolidated and strengthened his position as province-king of Munster. He went on forays into Mide and Leinster in 1089 and took the kingship of Leinster and fought for the Viking town of Dublin. In 1093, he accepted the submission of Domnall mac Flainn Ua Maíl Shechnaill, the Uí Néill king of Tara, and also made peace with his brother Diarmait at Cashel.
[edit] King of Ireland with opposition
In 1094, Muirchertach fought the kings of Leth Cuinn and Gofraid, king of Dublin. He went with his army to Dublin and banished Gofraid, and brought about the killing of Domnall Ua Maíl Shechnaill. He asserted supremacy over the Uí Néill kingdom of Mide.
In 1101 he declared himself High King and travelled the island provinces. It was in this year that he gave the fortress at on the rock of Cashel as a gift to the Church.
[edit] Alliance with Arnulf de Montgomery
In an effort to gain military support against Henry I, Arnulf de Montgomery sent his steward, Gerald of Windsor, to Ireland to negotiate terms with Muirchertach. According to a Welsh chronicle (Sean Duffy, p. 45, 1997), Arnulf "though to make peace with the Irish and to obtain help from them. And he sent messengers to Ireland, that is Gerald the Steward (Gerald of Winsor) and many others, to ask for the daughter of King Murtart for his wife. And that he easily obtained; and the messengers came joyfully to their land. And Murtart sent his daughter and many armed ships along with her to his aid. And when the earls had exalted themselves with pride because of those events, they refused to accept any peace from the king."
De Montgomery and his brother Robert, were however defeated by Henry and fled to Ireland. The Montgomery brothers fought under Muirchertach during his campaign with Magnus Barelegs, but when de Montgomery attempted to seize the kingship for himself, Muirchertach "took his daughter away from Arnulf and gave the wanton girl in an unlawful marriage to one of his cousins. He resolved to kill Arnulf himself as a reward for his alliance, but the latter ... fled to his own people and lived for twenty years afterwards with no fixed abode." (Sean Duffy, 1997, p. 46).
[edit] Magnus Barelegs
In 1102, Muirchertach cemented an alliance with Magnus Barefoot, king of Norway by marrying his daughter Blathmin Ua Briain to Magnus's son, Sigurd I Magnusson. Muirchertach now took part in a campaign with Magnus to assert control over Ulster, successfully defeating opposing Irish forces. After a year of campaigning, as his army was readying to depart back to Norway, King Magnus was ambushed and killed by an Irish army in Ulster. With Magnus's death, Muirchertach's daughters marriage was disavowed by the Norwegians, weakening Muirchertachs proclaimed position as High King.
In 1114 the king became sick to the point where "he became a living skeleton".[1] In response to the king's misfortune, his brother Diarmait took control of the kingship of Munster and banished Muirchertach. The following year Muirchertach regained his strength and undertook a campaign to regain control of Munster and successfully captured Diarmait. Only later did the king regain control of Munster.
[edit] Final years
In 1119, Muirchertach Ua Briain died.
see:
http://en.wikipedia.org/wiki/Muircheartach_Ua_Briain