Muirchertach Ua Briain

Muirchertach Ua Briain (anglicised as Murtaugh O'Brien; – , son of Toirdelbach Ua Briain and great-grandson of Brian Boru, was King of Munster and later self-declared High King of Ireland.

Background and early career

Muirchertach Ua Briain was a son of Toirdelbach Ua Briain, the previous Dalcassian King of Munster and de facto High King of Ireland. As a descendant of Brian Boru, he was part of the powerful O'Brien dynasty who ruled Ireland at the time. His mother was Derbforgaill, daughter of Tadhg Mac Giolla Pádraig of Osraige, who also bore Muirchertach's brother Tadhg.

His early life is largely unknown. The Annals of Tigernach give his birth date as 1050. Afterwards, he is not mentioned in any of the annals of Ireland until the year 1075 when he was defeated by the Kingdom of Airgíalla in battle near modern Ardee in County Louth, taking heavy losses. This was part of a series of campaigns undertaken by his father Toirdelbach against rebellious lesser kings in the north of the country. He was later appointed as king or governor of the city-state of Dublin by his father.

Governor of Dublin Background: Importance of Dublin

Despite the victory of Muirchertach's great-grandfather Brian Boru over the Vikings at the Battle of Clontarf in 1014 and the breaking of Norse power in Ireland, Dublin remained under the rule of Norse–Gael kings and had links with other Viking Kingdoms. They paid tribute to their Irish overlords, but otherwise the Irish rarely interfered, mainly because of the trade the Norse brought to the area.

King of Ireland In 1094, Muirchertach fought the kings of Leth Cuinn and Gofraid Crobán, King of Dublin and the Isles. 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 Southern Uí Néill of the Kingdom of Meath, dividing the province between two rival clans, applying a policy of divide and rule, which had been used very effectively by his father before him.

The Irish Sea and Magnus Barefoot

Since the Kingdom of Dublin had fallen to the Irish of Leinster in the year 1052, Irish influence in the Irish Sea, particularly the Kingdom of Man and the Isles, had greatly increased. Diarmuit mac Maíl na mBó, King of Leinster and High King of Ireland, was also King of the Isles through capturing Dublin as Dublin was part of this Kingdom. Having ousted the Norse–Gael king, he was in a very powerful position. After Diarmuit's death, Muirchertach's father, Toirdelbach, became High King of Ireland and had control of Dublin. He was involved in the Isle of Man as well, more or less controlling the island, possibly through one his sons, Tadc, brother of Muirchertach, marrying a woman from the Manx royalty. The work was intended to romanticize the accounts from the annals, in a bid by Muirchertach to secure the O'Brien Dynasty's claim to the High Kingship, in a time when the throne was fiercely contested by the Northern Uí Néill in Ulster and later, the Ua Conchobhairs of Connacht.

An Sligeadh Timcheall

In 1101, officially High King of Ireland and with the Church on his side, Muirchertach planned his largest and most ambitious campaign yet, called An Sligeadh Timcheall ("The Circular Hosting"). He gathered the armies of the various kingdoms, save those of Ulster, and marched northwards. The six-week long campaign began with his army marching north to the River Erne at Assaroe, then to the Inis Eoin Peninsula, burning Ardstraw and Fahan on the way. The offensive culminated with the destruction of Grianan an Aileach, an important fort of the Northern Uí Néill, in revenge for Ua Lochlainn's earlier burning of towns in Munster. Muirchertach famously ordered his men to bring back one stone from the walls of the fort for every sack of provisions they had. They marched home to Munster along the ancient route of Slige Midluachra.

For the first time during his reign, he had successfully subdued the Ulaid. The Northern Uí Néill had been severely weakened, but did not capitulate. Muirchertach would lead several campaigns against Ua Lochlainn over the next few years, but was unable to gain their submission, with the campaign almost always ending in stalemate in southern County Armagh. With the Ulaid now under his control, however, he had another angle from which to attack the Uí Néill from in the Northeast, and easier access to the Hebrides and other areas of the Isles, and parts of Scotland.

Campaigns in the North and Second War in the Irish Sea Like many of the High Kings of Ireland from the South had found, including Muirchertach's great-grandfather Brian Boru, the last place to recognise their authority was Ulster, namely the Kingdoms of Ulaid and the Northern Uí Néill. At the turn of the century, Muirchertach led annual campaigns against Domhnall Ua Lochlainn and the other northern kings, with mixed success. Muirchertach's armies consisted of soldiers from every Irish Kingdom apart from Ulster. The fighting was often heavily concentrated in what is now modern southern County Armagh, but Muirchertach would often be halted by the intervention of the comrade Patraic, the abbot of Armagh, who would organise truces between the two kings.

Muirchertach attempted a campaign against the Cenél Chonaill, with naval support from the fleet of Dublin, but he was forced to retreat following the destruction of the Dublin fleet. Around the same time, Muirchertach was also under threat from Magnus Barefoot of Norway, who had returned with a larger force than his first Irish Sea campaign, possibly with the intention of invading Ireland. Magnus had earlier raided Inis Cathaigh (Scattery Island) at the Shannon estuary in 1101, possibly testing the situation and defenses of Ireland.

Magnus agreed to provide military support for the High King in his war against the men of Ulster. They forged an alliance, cemented by the marriage of Muirchertach's daughter, Bjaðmunjo, to Magnus's son, Sigurd. The treaty also saved Ireland from Norse raids, but the Irish lost most of their control in the Isles to the Norwegians. Muirchertach also recognised Norwegian control over Dublin and Fingal, with the western lands of the Kingdom of Norway under the control of Sigurd, who was announced as co-king alongside Magnus on the day of his wedding.

Muirchertach and Magnus campaigned together in Ulster throughout late 1102 and early the next year. Contrary to the Norse sagas, the Irish Annals describe the campaigns as largely unsuccessful. Norse sources say Magnus spent the winter in the High King's palace at Kincora in Killaloe with Muirchertach, but it is also possible that he wintered in Dublin.

There is confusion surrounding the death of Magnus. Norwegian sources say Muirchertach was supposed to bring Magnus provisions for his return to Norway. When Muirchertach did not show up at the agreed time, Magnus became suspicious the Irish were going to attack. On 24 August 1103, St. Bartholomew's Day—or the day before, according to one source—Magnus gathered his army and landed on the coast of northeastern Ireland. It is possible he made an incautious cattle raid, and the Ulaid mistook the Norwegians for cattle-raiding Hebrideans. Alternatively, it is possible that Muirchertach ordered the Ulaid to bring Magnus supplies, but the Ulaid took this is an order to ambush him.

De Montgomery and his brother Robert were defeated by Henry, however, and fled to Ireland. The Montgomery brothers fought under Muirchertach during his campaign with Magnus Barefoot, 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."

According to Orderic Vitalis, Muirchertach only allowed the Normans to stay in case he needed their support to fight Magnus if he were to violate their treaty and attack the Irish. However, after the Norwegian King's death at the hands of the Ulaid, Muirchertach turned against the English rebels and forced them out of Ireland, possibly in an attempt to make amends with Henry. Indeed, Henry had imposed sanctions on Irish trade for their assistance in helping the rebels, but Muirchertach was able to negotiate the lifting of the embargo (possibly by handing Arnulf over to the English), while also again demonstrating his skill in diplomacy.

Munster was divided into three Kingdoms: the Kingdom of Thomond under the O'Brien dynasty, the Kingdom of Desmond under the MacCarthy Mór dynasty, and the Kingdom of Airgíalla under the Kennedys, although the last was short-lived. Muirchertach apparently went into retirement having lost his High Kingship, and died at Lismore, modern County Waterford, a year later in 1119. He was succeeded by Toirdelbach Ua Conchobhair as High King of Ireland, who would prove to be one of the greatest High Kings in the history of Ireland. Although the O'Briens never reclaimed the High Kingship, the Kingdom of Thomond remained a powerful kingdom for the next few centuries.

Assessments Anthony Candon (1979, p. 398) remarked of Ó Briain:

Muirchertach Ó Briain was an ambitious, modernising and outward-looking king whose goal was to make himself king of Ireland as much as William Rufus and Henry I were kings of England; in reality his position was, perhaps, more analogous to that of Philip I in France ... but his actual authority in Ireland, especially at the height of his power in the first years of the twelfth century, greatly exceeded that of Phillip in France. ... Ua Briain ... pursued a vigorous foreign policy which was to carry his activities beyond his own shores.

In the latter regard, Candon (1979, p. 415) views

Ua Briain's activities in the Irish Sea area [as] a mixture of old and new, of pragmatism and idealism ... But they are invested with a modern purpose. Ua Briain makes one marriage with the king of Norway, and another with one of the most powerful non-royal families in Europe; he treats with the king of Scotland; his aid to the Welsh princes acts as a stabilising influence in Welsh politics; he incurs trade sanctions from the king of England, and negotiates their suspension. Altogether, Muirchertach Ó Briain lifted his head above the domestic power struggle and sought to involve Ireland in the international politics of Europe, so that some sixty years later, these activities were still well remembered, and are reflected in the vitae of St. Flannan of Killaloe.