High Kings of Ireland
Medieval Irish historical tradition held that Ireland had been ruled by an Ard Rí / High King since ancient times, and compilations like the Lebor Gabála Érenn, followed by early modern works like the Annals of the Four Masters and Geoffrey Keating‘s Foras Feasa ar Éirinn, purported to trace the line of High Kings, but national kingship was never a historical reality in Ireland before the C11th.
The corpus of early Irish law does not support the existence of a political High King, and most scholars now regard it as a pseudo-historical construct of the C8th AD, a projection into the distant past of a political entity which did not become a reality till relatively shortly before the arrival of the Normans.
The High Kingship was strongly associated with Tara, traditionally regarded as the capital of Mide (Meath), the smallest of the five major kingdoms / overlordships of Gaelic Ireland.
Tara was undoubtedly a place of ritual gatherings since pre-historic times, and some believe that the king of Tara had some sort of symbolic religious role in Pre-Christian Ireland, possibly involving sacrifices. The title king of Tara was, even from the perspective of its earliest historical holders, imbued with a mythical aura stretching back deep into the past, a powerful status based on a barely remembered tradition of a sacred King of kings.
From the C5th AD onwards, Mide was held by various members of the Uí Néill / O’Neill clan, who also wielded power in parts of Ulster, and appear to have used the title king of Tara to denote overlordship of their kindred and realms. However, they had little or no power in other parts of Ireland.
Most importantly, most of the southern part of the island was effectively under the control of the Eóganachta dynasty in Cashel. The Eoganachta were governed for five centuries by a succession of warrior bishops, several of whom were acknowledged as Ard Rí / High Kings of Ireland, at least in the Leth Cuinn (Southern half of Ireland), i.e. Mumha (Munster)and Laigin (Leinster).
Tara rulers like Máel Sechnaill mac Máele Ruanaid declared themselves as King of All Ireland, but he was not even able to maintain peace with his own Uí Néill kinsmen, and later such claims did not gain the political support of other kingdoms, the Norse or Norse-Gaels.
The traditional list of High Kings of Ireland is thus a mixture of fact, legend, fiction, and propaganda. The individuals appearing prior to the C5th AD are generally considered legendary, and the application of the title to individuals before the C9th is anachronistic.
Lists of legendary and semi-historical High Kings can be seen here.
Late Prehistoric kings of Tara
Niall of the Nine Hostages
Lóegaire mac Néill
Coirpre mac Néill
Historical kings of Tara
Mac Cairthinn mac Coelboth d. 446/447
Tuathal Maelgarb d.544/549
Diarmait mac Cerbaill, before 558-565
Forggus mac Muirchertaig and Domnall mac Muirchertaig 565-569?
Báetán mac Muirchertaig and Eochaid mac Domnaill 569? -572/573
Ainmuire mac Sétnai 572/573-575/576
Áed mac Ainmuirech 575/576, or 592 – 598
Fiachnae mac Báetáin (Fiachnae Lurgan) 589-626
Colmán Rímid mac Báetáin and Áed Sláine mac Diarmato 598 – 604
Áed Allán mac Domnaill (Áed Uaridnach), “king of Temair”, 604 – ?
Congal Cáech d. 637
Cathal mac Finguine 713-742
Áed Allán 730-738
Donnchad Midi mac Murchado 763-797
Áed Oirdnide mac Néill 797-819
Conchobar mac Donnchada 819-833
Niall Caille mac Áeda 833-846
Historical High Kings of Ireland
Máel Sechnaill mac Máele Ruanaid (846–860)
Aed Findliath mac Néill (861–876)
Flann Sinna mac Máelschnaill (877–914)
Niall Glúndub (915–917)
Donnchad Donn mac Flainn (918–942)
Congalach Cnogba mac Máelmithig (943–954)
Domnall ua Néill (955–978)
Máel Sechnaill mac Domnaill (979–1002m restored 1014–1022)
Brian Bóruma (1002–1014), self-styled “Emperor of the Irish”
The annalists frequently describe later High Kings as rígh Érenn co fressabra (“Kings of Ireland with Opposition”). Máel Sechnaill had been overthrown by Brian Boru in 1002, and restored in 1014 following Brian’s death, but the example of Brian’s coup was followed by numerous other families in the century following 1022.
Donnchad mac Briain (d. 1064) (with opposition)
Diarmait mac Maíl na mBó (d. 1072) (with opposition)
Toirdelbach Ua Briain (d. 1086) (with opposition)
Domnall Ua Lochlainn (d. 1121) (with opposition)
Muirchertach Ua Briain (d. 1119) (with opposition)
Toirdelbach Ua Conchobair (d. 1156)
Muirchertach Mac Lochlainn (d. 1166)
Ruaidrí Ua Conchobair / Rory O’Connor (d. 1198)
The Norman quasi-conquest of Ireland in 1171 effectively ended the High Kingship, although the title was claimed for several centuries by descendants of Ruaidrí Ua Conchobair / Rory O’Connor.