Diarmait Mac Murchada

Diarmait Mac Murchada was born in 1110 into the ruling dynasty of Leinster, the province occupying the southeast of Ireland. His family, the Uí Chennselaig, had held the Leinster kingship for generations from their power base around Ferns in modern County Wexford ^[1]. His father, Donnchad mac Murchada, was king of Leinster and of the Norse town of Dublin until he was killed in battle in 1115, when Diarmait was still a small child. Later tradition held that the Dubliners buried Donnchad with the carcass of a dog, a calculated insult that the family never forgot ^[2].

Anyone asking who was Diarmait Mac Murchada has to begin with the violent politics of twelfth century Ireland. The island had no settled central monarchy. Provincial kings fought constantly for the high kingship, and succession within each dynasty was contested among brothers, cousins, and uncles rather than passing automatically to an eldest son. Diarmait grew up in this world of shifting alliances, cattle raids, and blindings of rivals, and he learned its rules early ^[1].

His elder brother Énna held the Leinster kingship after their father's death. When Énna died in 1126, Diarmait, then about sixteen, was put forward for the throne. The high king Toirdelbach Ua Conchobair of Connacht tried to impose his own son on Leinster instead, and Diarmait spent his first years as claimant fighting to make his title real. By 1132 he had secured effective control of the province ^[3].

Diarmait consolidated power with methods that were harsh even by the standards of his age. The Irish annals record that in 1141 he moved against the rival aristocracy of north Leinster, killing or blinding numerous dynasts who might have challenged him ^[3]. The purge worked. For the next quarter century he faced no serious internal rival, and he could turn his energy outward toward Dublin, the wealthy Norse trading town his dynasty had long claimed, and toward the wider contest for supremacy in Ireland.

He was also, in a pattern common among ambitious medieval kings, a substantial patron of the church. He founded the Cistercian abbey of Baltinglass around 1148, established the convent of St Mary de Hogges in Dublin, and endowed All Hallows Priory on the site later occupied by Trinity College Dublin ^[4]. He supported the reforming wing of the Irish church and secured the election of his wife's kinsman Lorcán Ua Tuathail, later canonized as St Laurence O'Toole, as archbishop of Dublin in 1162. The great manuscript known as the Book of Leinster was compiled in circles close to his court, and its contents reflect the dynasty's view of its own past ^[1].

In the struggle for the high kingship Diarmait attached himself to Muirchertach Mac Lochlainn, the powerful king of the north. The alliance paid off: with Mac Lochlainn's backing Diarmait held Dublin and stood among the strongest provincial kings in Ireland during the 1150s and early 1160s ^[3]. His position, however, depended entirely on his patron's survival, a weakness that would soon be exposed.

The most notorious of all Diarmait Mac Murchada facts concerns events of 1152. In that year, while his enemy Tigernán Ua Ruairc, king of Bréifne, was politically vulnerable, Diarmait carried off Ua Ruairc's wife Derbforgaill along with her cattle and goods ^[2]. The annals suggest the affair was arranged with the connivance of Derbforgaill herself or her family, and she returned to Bréifne the following year. Whatever the truth of her consent, the episode humiliated Ua Ruairc and created a personal feud that lasted the rest of both men's lives.

Later writers, beginning with Gerald of Wales in the 1180s, dressed the abduction up as the cause of the Norman invasion, casting Derbforgaill as an Irish Helen of Troy ^[5]. Modern historians treat that framing with caution. The raid was one move in a long territorial rivalry, and fourteen years passed before its consequences caught up with Diarmait. But the memory mattered. When the political wheel turned, Ua Ruairc made sure the debt was paid in full ^[3].

The turn came in 1166. Muirchertach Mac Lochlainn was killed, and the kingship of Ireland passed to Ruaidrí Ua Conchobair of Connacht, an ally of Ua Ruairc. The new high king marched on Leinster with Ua Ruairc and the Dubliners, who still nursed their own grievances against the Uí Chennselaig. Diarmait's vassals deserted him, his stone house at Ferns was burned, and he was formally deposed. In August 1166 he took ship from Ireland with a small household, an exiled king in his mid fifties with nothing left but determination ^[2].

Rather than accept defeat, Diarmait sailed to Bristol and then travelled through England and France in search of Henry II, the Angevin king whose dominions stretched from Scotland's border to the Pyrenees. He found Henry in Aquitaine, did homage to him, and asked for help in recovering Leinster. Henry, occupied with his continental affairs, declined to intervene personally but gave Diarmait letters authorizing any of his subjects to take service with the Irish king ^[6].

Armed with that licence, Diarmait recruited in the Welsh marches, where land hungry Norman, Flemish, and Welsh fighting men were plentiful. His crucial catch was Richard fitz Gilbert de Clare, lord of Striguil, known to history as Strongbow. Diarmait promised him marriage to his daughter Aífe and, remarkably, succession to the kingdom of Leinster itself, an offer with no basis in Irish law, under which kingship was elective within the dynasty rather than heritable through a daughter ^[6]. He made lesser bargains with Robert fitz Stephen, Maurice fitz Gerald, and other members of the Geraldine kindred, promising them the town of Wexford and adjoining lands.

Diarmait slipped back to Ireland in August 1167 with a handful of mercenaries and quietly reoccupied his home territory around Ferns. Ruaidrí Ua Conchobair confronted him but allowed him to keep his ancestral lands on hostage terms, and Ua Ruairc extracted one hundred ounces of gold as compensation for the insult of 1152 ^[3]. It looked like a settlement. Diarmait treated it as a pause.

The main Norman force arrived in May 1169, when Robert fitz Stephen landed at Bannow Bay on the Wexford coast with knights, men at arms, and archers. Joined by Diarmait's Irish troops, they took the town of Wexford, and within months Diarmait had recovered control of Leinster ^[5]. Among the chief Diarmait Mac Murchada achievements, if the word can be used of so ruthless a career, was this feat of political resurrection: a deposed king in his late fifties clawing back an entire province in three years.

Strongbow himself landed near Waterford in August 1170 with a larger army. The city fell after hard fighting, and the promised marriage between Strongbow and Aífe was celebrated there almost immediately. In September the combined forces seized Dublin, driving out its Norse ruler. Diarmait, his ambition swelling with success, raided into Meath and Bréifne against his old enemy Ua Ruairc and began to speak of the high kingship of Ireland itself. Ruaidrí Ua Conchobair executed the hostages Diarmait had given him, including one of Diarmait's own sons, but could not stop the Norman advance ^[6].

Diarmait did not live to see how the story ended. He died at Ferns on May 1, 1171, aged about sixty one. The annalists, who despised him, recorded his death with venom: the Annals of the Four Masters describe him as the man who had made a trembling sod of all Ireland and claim he died of an insufferable disease, without a will, without penance, in reparation for his misdeeds ^[2]. Strongbow claimed Leinster in right of his wife, and within months Henry II himself landed in Ireland to assert royal authority over both the Normans and the Irish kings.

Few reputations in Irish history sit lower. From the later Middle Ages onward Diarmait was remembered as Diarmait na nGall, Diarmait of the Foreigners, the king who invited the English into Ireland. Nationalist writing of the nineteenth and twentieth centuries fixed him as the archetypal traitor, and his name is still used in Ireland as shorthand for betrayal ^[7]. The judgment is understandable: the intervention he engineered led directly to Henry II's lordship of Ireland in 1171 and to eight centuries of English and British involvement in the island.

Historians writing any serious Diarmait Mac Murchada biography now complicate that verdict without overturning it. Within the norms of twelfth century Irish politics, hiring foreign soldiers was routine; Irish kings had long employed Norse fleets and Hebridean mercenaries. What set Diarmait apart was the scale of his promises, above all the grant of Leinster's succession to Strongbow, which converted a mercenary contract into a permanent colonial foothold ^[6]. He could not have foreseen the full consequences, but he accepted risks no other Irish king had taken.

His blood, ironically, ran through both sides of the world he created. Through Aífe and Strongbow's daughter Isabel de Clare, ancestors of the Marshal earls and much of the later English aristocracy, Diarmait became a forebear of countless prominent families, including later English and British monarchs. In Ireland his descendants through his son Domnall Cáemánach, the MacMurrough Kavanaghs, kept a diminished Leinster kingship alive into the sixteenth century ^[1]. Ferns, his old capital, preserves the ruins of the abbey he founded, where tradition places his grave ^[4].