History Files


Gaelic Kingdoms

Kingdoms of Ireland




Ireland / Erin

Settled at some point after about 500 BC by the Indo-European Celts, Ireland was never conquered by the Romans. Instead the Irish helped to hasten the end of Roman control over Britain by constantly raiding the British coastline, capturing slaves and booty. They were converted to Christianity by the Romano-British Saint Patrick in the mid-fifth century. Isolated from the chaos that swept Britain during the Anglo-Saxon invasion, Ireland was able to develop its own rich and prominent Christian culture. During the sixth century, Saint Columba followed in the footsteps of the Irish Scotti to spread the Celtic Church into Dal Riada (now western Scotland), while in western Wales, the Deisi had settled and helped to form the kingdom of Dyfed.

Ireland was never politically unified enough to translate its religious and cultural influence into political power. There were some signs that unity would have eventually come, however. At various points in its later history, from the eighth or ninth centuries onwards, Ireland was united under the high kings (ard ri), and, but for many incursions by Danes, Normans and the English, Ireland might have developed into a fully unified single kingdom in the same way as England had in the tenth century. The later high kings were nominally in charge, but in practice, descended as they were from the prominent Ulster Ui Neill / O'Neill Clan, the only territory under their command without dissent was Ulster, while for the earlier high kings, the title was more of a ceremonial one, and never implied political control of the whole country.

The earliest priest-kings who claimed the high kingship are often legendary, with little or no proof of their actual existence bar oral history. As such, where necessary, they are shown over a lilac-tinted background.

The first written record of contact with 'Albion' (Greek) names both Britain/Alba and Ireland as the 'Prettanik' islands. That is the oldest known name, which then leaves them to be distinguished from each other by Alba (meaning 'white', probably named after the chalk cliffs of Dover), and Hibernia, which is the rather sloppy Latin translation of Ierne as written by the Greeks. Ierne is fairly obviously a mispronunciation of Er Inis or Eire Innis (various spellings are available), meaning 'West Island' in common Celtic. Er Inis became shortened to Erin. The name remains in use today in its full form - Eireann.

(Additional information by Edward Dawson.)

c.2000 BC

A discovery in 2011 of a bog body in central Ireland sheds light on possible early kingship rules. Known as 'Cashel Man', the Bronze Age body is found in County Laois and may be the earliest bog body with intact skin known anywhere in the world (to date).

Archaeologist Eamonn Kelly suggests that all of the known bog bodies, all of which are male and aged between twenty-five and forty, have suffered violent deaths as victims of human sacrifice. When an Irish king is inaugurated, he is inaugurated in a wedding to the goddess of the land. It is his role to ensure through his marriage to the goddess that the cattle will be protected from plague and the people will be protected from disease. If these calamities should occur, the king will be held personally responsible. He will be replaced, paying the price for his failure with his sacrifice. Cashel Man fits this pattern because his body lay on a border line between territories and within sight of the hill upon which he would have been crowned. He has suffered significant violent injuries to his back, and his arm shows evidence of a cut from a sword or axe.

Cashel Man
The Cashel Man bog body has been compressed by 4000 years of peat build-up, but his outstretched hand can still be made out above his legs (to the left of the picture)

c.1100 BC

There is evidence, supported by archaeology, of an early influx of Celts into Britain, where they eventually push back or integrate with the indigenous population and settle in the fertile south and east. They also later infiltrate into Ireland. This would explain later tradition which claims the conquest of the island of Britain by Brutus. This influx, however, would be little more than a new elite ruling the native Bronze Age population of the islands.

c.650 BC

The Cadurci tribe of Celts are thought to migrate across the Rhine, leaving the Celtic heartland in southern Germany to enter the land that becomes known as Gaul. The Lexovii make the same journey. Other Celtic groups are also settling in the British Isles and Ireland around this time.

fl c 360s BC?

Partholón / Partholoim / Partholomus

Legendary king who was the first to settle Ireland.

FeatureIn Irish mythology, Partholón is the leader of the first settlement in Ireland after the Mesopotamian Great Flood. Geoffrey of Monmouth mentions him in conjunction with High King Gurguit Barbtruc of Britain, probably finding him in the Historia Britonum (Chapter 13), the ninth century Welsh Latin historical compilation put together by Nennius.

c.56 BC

The fleet of Roman general Julius Caesar defeats the Veneti off the coast of what becomes known as Armorica. Elements of the tribe may flee to Britain and Ireland where they form two tribes of Venicones, one in what becomes Pictland and the other in County Donegal, where both are attested by Ptolemy by AD 140.

55 - ? BC

During or following the conquest of Gaul by the Romans, many tribes flee either in their entirety or in smaller groups, heading for Britain and Ireland. Among these are the Menapii, who establish a colony in modern County Kilkenny and the west of County Wexford in Ireland. A little over a century later, elements of the Brigantes join them, settling immediately to their south.

fl c.20 BC

Matholug / Matholwch

King of Ireland.

FeatureThe Mabinogion contains the tale of Branwen, daughter of Penardin White Throat (or Penarddun), sister of the high king of Britain. When her brother, Bran, becomes high king he is approached by Matholug, who asks for Branwen's hand in marriage. Branwen is taken back to Ireland where she gives birth to a son, Gwern. An insult paid to Matholug by the troubled Emnissien, Branwen's half-brother, plays on his mind so, at the urging of his advisors, Branwen is consigned to captivity in his kitchens. When Bran hears of this, he leads a mighty host which defeats the Irish king. Despite a truce, further fighting erupts, devastating both sides and resulting in the deaths of Bran, Emnissien, Gwern, Matholug and, eventually, Branwen.

1st century AD

The Celtic tribe of the Concani or Gangani are situated in territory that later becomes Leinster. The tribe (or tribes) appears to be split between Ireland and Britain. In the latter it is called the Deceangli or Gangani.

AD 72 - 79

Some archaeological evidence from the island of Lambay, and a second century map by Ptolemy, reveal the possibility that some Brigantine elements flee to Ireland and settle there following the conquest of their kingdom by the Romans. It is only towards the end of the century that Brigantine artefacts start to appear in Ireland (in the Cork/Waterford area). Elements of the Deceangli may also flee to Ireland by the end of the decade to escape Roman rule and retribution.

fl 2nd century

Conn of the Hundred Battles

'High King' of Ireland.

Art mac Cuinn

Son. 'High King' of Ireland.

Cormac mac Airt

Son. 'High King' of Ireland.

According to legend, Cormac mac Airt is high king of Ireland ('Ard Ri na Eireann') during the time of Finn mac Cuill.

360 - 361

At the start of 360, Roman Caesar Julian (the Apostate) is wintering in Lutetia Parisiorum (the early Paris) when reports reach him that the Scotti and Picts have broken a previous agreement (perhaps made in 343) and are plundering lands close to the frontier, presumably those of the Novantae and Selgovae. Whether the campaign goes ahead under a less senior commander after the original commander is recalled is unknown.

fl 4th century

Eochaid Mugmedon

Great-great-great-great-grandson of Conn.

Eochaid Mugmedon spawns several dynasties that subsequently rule the provinces of Connacht, Mide, and Ulster into the middle ages. These dynasties are known by the names of Eochaid's four sons, being the Ui Bruin, Ui Fiachrae, Ui Aillil, and Ui Neill.


According to Ammianus Marcellinus, the Picts, Scotti, Saxons, and Attacotti attack Roman Britain in what seems to be a serious incursion.


The Barbarian Conspiracy sees attacks falling on Roman Britain from all sides, including from the Scotti.

379 - 405

Niall Noígillach of the Nine Hostages

Ruled from Tara. First non-legendary High King?


By now the territory of the Deceangli and Ordovices in Britain is under severe threat by waves of Irish raiders. The situation is so bad that much of the land of these tribes is incorporated into a new territory when Cunedda Wledig and his branch of Romanised Venicones are transferred from the Manau dependency of the Goutodin to secure north Wales from the raiders. They are extremely successful, and the kingdom of Gwynedd is formed by them.


Attacks on the south coast of Britain by Niall are best associated with this year.

405 - 428

Dathi / Nath I


Immediately prior to Vortigern's apparent rise to power as High King of Britain, the country is subjected to raids along its coastline. In the west, Irish raiders sail up the Severn and seize a large amount of booty in the form of corn, cattle and anything else they can grab, including sons and daughters. They are also credited with kidnapping the young St Patrick from the College of Theodosius (at Llantwit Major, which would place the raid within the territory of Cernyw).

429 - 463

Lóeguire macNéill

First Ui Neill High King?


After consecrating St Palladius in Rome in 431, Pope Celestine send him to Ireland as its first bishop, part of the British Church's efforts to convert their Scotti neighbours. He is the country's first bishop.


Lóeguire, or Loegaire, is said to be on the losing side in a druidic contest with St Patrick over the lighting of the Easter Fire.


Despite apparently holding the territory under his command in relative safety for up to forty years, Eugenius meets his end in battle, probably against Irish raiders. His son succeeds him in ruling what is now certainly the kingdom of Cernyw, rather than a possible protectorate or Romanised territory of mid-south Wales.


FeatureThere is a probably Irish presence at Dunster Castle in the early post-Roman period. This is a fort which overlooks the approaches to Exmoor, four and-a-half kilometres (three miles) south-east of Minehead in Somerset (roughly on the edges of Dumnonian territory). The modern castle may not be the same site as the post-Roman fort, which could be located a little way inland. Irish settlers are frequenting Somerset at this time, which suggests that they are people who have already been accepted into Britain, such as the Deisi of Dyfed. They are not large in number but they do remain for a long time. Nearby Glastonbury is spoken of as 'Glastonbury of the Gaels' thanks to its shrines of St Patrick and St Brigit. The fort features in the list of twenty-eight cities of Britain in Nennius' Historia Brittonum, appearing as Caer Draithou.


MapDuring a time of large-scale unrest in Britain, the Saxon foederati based around the country rebel and pillage the country in the face of light British opposition. During this time, Irish raids on the west become heavier, and one Irish band captures Powys in the West Midlands.

463 - 483

Ailill Motl mac Nath I


St Patrick had possibly been born as Maewyn Succat at Banna Venta Berniae in Britain (location unknown, but subject to much speculation). Around this year, he returns to Ireland as a Christian missionary of the British Church following a period of six years of captivity there as a slave from the age of sixteen. As the country's second bishop (after Palladius), he plays a major part in converting the Irish to Christianity. According to legend, he also rids Ireland of its snakes, which is probably a reference to his driving out of paganism.

483 - 507

Lugaid macLóeguiri O'Néill

c.480 - 550

During this period, the domination of the High Kings pressurises the Scoti, in the north and east of Ulster, into migrating to western Pictland. Once there, they found the Dal Riada kingdom.


This is the generally-agreed date of death for Patrick, patron saint of Ireland. His efforts in converting the Scotti is sometimes confused, and combined, with those of Palladius, who precedes him in the same work for the British Church by a couple of generations, having been sent there in 431,


Tristan, son of Meirchion of Lyonesse, is one of the main characters of the story of Tristan & Iseult. While bringing Iseult, daughter of the Irish king, to Cornubia where she would marry King Mark, the two people fall in love. They have a secret affair which is belatedly discovered by Mark. Tristan manages to escape, but the couple are later forgiven. Unlike some later works, Tristan & Iseult portrays Mark in a sympathetic fashion. Later works paint him in increasingly darker tones, making him more and more evil and less of a sympathetic figure.

507 - 534

Muirchertach macErcae O'Néill

King of Ulster.

534 - 544

Tuathal Máelgarb macCorpri Cáech O'Néill

544 - 565

Diarmait macCerbaill O'Néill

Last pagan High King.

According to the Irish Annals, Diarmait macCerbaill is cursed by St Ruadhán of Lorrha. This represents the end of pagan kingship in Ireland and the rise of the new Christian way of life. Tara is abandoned around the same time, its role as a centre of pagan druidry and sacral kingship outliving its usefulness. However, its reputation as a place of greatness lives on in Irish minds, and the later High Kings do much to foster this reputation.

565 - 566

Domnall macMuirchertaig O'Néill

565 - 566

Forggus macMuirchertaig O'Néill

566 - 569

Ainmere macSátnai O'Néill

569 - 572

Báetán macMuirchertaig O'Néill

569 - 572

Eochaid macDomnaill O'Néill

572 - 581

Báetán macNinnedo O'Néill

Also known as mac Cairill. King of Ulster.

581 - 598

Aed macAinmerech O'Néill

598 - 604

Aed Sláine macDiarmato O'Néill

598 - 604

Colmán Rímid macBáetáin O'Néill

Rival claimant.

604 - 612

Aed Uaridnach macDomnaill O'Néill

612 - 615

Máel Cobo macAedo O'Néill

615 - 628

Suibne Menn macFiachnai O'Néill


The Book of Leinster (190a) makes mention of a tale, now lost, entitled Sluagad Fiachna maic Báitáin co Dún nGuaire i Saxanaib, 'The Hosting of Fiachna son of Baitan to Dun Guaire in Saxon-land'. The Fiachna mentioned in the title is a son of Baetan mac Cairill, king of Ulster (died 581). He is a famous warrior who is killed in 626. The Dún Guaire mentioned is the Irish form of the British Din Guayroi, the native name of Bebbanburch (modern Bamborough), the capital of Bernicia.

The Annals of Ulster also mention an event for 623, 'expugnatio Ratho Guali la Fiachna mac Báetáin', 'the storming of Rath Guali by Fiachna son of Baetan'. The details of the event seem to have been lost, but in general terms, an Irish raiding party led by Fiachna, son of Báetán seems to have attempted to storm the Bernician stronghold of Bamborough. Given the fact that the Bernicians had already weathered half a century of similar attacks by Britons, it seems a rather foolish expedition, and it results in Fiachna's death.

628 - 642

Domnall macAedo O'Néill

642 - 654

Conall Cóel macMáele Cobo O'Néill

642 - 658

Cellach macMáele Cobo O'Néill

656 - 665

Diarmait macAedo Sláine O'Néill

Joint ruler.

656 - 665

Blathmac macAedo Sláine O'Néill

Joint ruler.

665 - 671

Sechnussach macBlathmaic O'Néill

671 - 675

Cenn Fáelad macBlathmaic O'Néill

675 - 695

Finsnechtae Fledach macDúnchada O'Néill

695 - 704

Loingsech macOengus O'Néill


A Celtic Church synod is allegedly held at Tara by Adamnan, abbot of Iona, who is also the biographer of the life of St Columba.

704 - 710

Congal Cinn Magir macFergus Fánat O'Néill

710 - 722

Fergal macMáele Dúin O'Néill

And Cenél Ailech.

722 - 724

Fogartach macNéill O'Néill

724 - 728

Cináed mac Irgalaig

724 - 734

Flaithbbertach macLoingsig O'Néill

Died in 765.

734 - 743

Aed Allán macFergal O'Néill

743 - 763

Domnall Midi O'Néill

763 - 770

Niall Frossach macFergal O'Néill

Died in 778.

770 - 797

Donnchad Midi macDomnaill Midi O'Néill

797 - 819

Aed Oirdnide macNéill Frossach O'Néill

819 - 833

Conchobar macDonnchado Midi O'Néill

833 - 846

Niall Caille macAedo Oirdnide O'Néill


Vikings set up a settlement of their own in a place called Dublin, a longphort or ship camp of extremely large proportions.


Shortly before becoming high king, Máel Sechnaill is recorded by the Annals of Ulster as capturing and drowning the first Viking king of Dublin, Thorgest.

846 - 862

Máel Sechnaill macMáele Ruanaid O'Néill

King of Mide.

862 - 879

Aed Findliath macNéill Caille O'Néill

Cenél Ailech.

865 - 870

Ivarr the Boneless and his brothers, sons of Ragnarr Lothbrok, king of Denmark, lead the first Viking army from Dublin to invade mainland Britain in search of conquest rather than pillage. They conquer Northumbria in 867. East Anglia falls in 869-870, and the capital of Alt Clut is sacked in 870.

879 - 916

Flann Sionna macMáele Sechnaill O'Néill

King of Mide.


The combined forces of Leinster and Brega expel the Vikings from Dublin.

916 - 919

Niall Glúndubh macAedo Findliath O'Néill

Cenél Ailech.


Sihtric and Ragnald, both descendants of Ivarr the Boneless, lead separate fleets in an attack on Ireland. While Ragnald is initially defeated by Niall Glúndubh, Sihtric turns the tables and defeats the High King's army. The Vikings resettle Dublin and re-found their kingdom.

919 - 944

Donnchad Donn macFlann O'Néill

944 - 956

Congalach Cnogba macMáel Mithig O'Néill


One of Congalach Cnogba's first acts is to sack Viking Dublin from his base in Brega, adding to the weakened kingdom's woes. The new Viking king is Olaf II, an ally of Congalach's, and it is possible that the two band together to fight off the rival for the High Kingship, Ruaidrí ua Canannáin.

944 - 950

Ruaidrí ua Canannáin

Rival claimant.

956 - 980

Domnall macMuirchertaig O'Néill

980 - 1002

Máel Sechnaill macDomnaill O'Néill

Nephew. Half brother to Glúniairn by his mother.


Máel Sechnaill conquers Viking Dublin, the first time the Irish kings manage to achieve this. As a result, some Irish date the founding of Dublin to this year (or 988), despite its ancient heritage. Máel appoints his half-brother, Glúniairn, to rule the Viking kingdom.


Glúniairn is killed in Dublin, apparently by his own slave when he is drunk, although the death is more likely to be the result of factional in-fighting in Dublin. Máel Sechnaill descends on the kingdom and installs Sitric Silkbeard, another son of Olaf, as king.


Máel Sechnaill is dethroned by Brian Bóruma - Brian Boru - and Viking Dublin, never entirely conquered, fights back.

1002 - 1014

Brian Bóruma macCennétig / Brian Boru

King of Munster (976-1014).


Brian Boru defeats the Dublin Norse at the Battle of Clontarf, but dies in the process, destroying Irish unity.

1014 - 1022

Máel Sechnaill macDomnaill O'Néill



Máel Sechnaill's restoration has brought a relative amount of peace during his reign, but his death marks the beginning of a period of internecine warfare as Leinster, Munster, and Connacht fight for control of Ireland, making it easier for the Normans to invade in 1171.

1022 - 1064

Donnchad MacBrian

King of Munster (1022?-1064).

1064 - 1072

Diarmait MacMáil na mBó

King of Leinster, and ruler of Dublin (1070-1072).

1072 - 1086

Toirdelbach O'Brien

King of Munster, and ruler of Dublin (1072-1074?).

1086 - 1090

Muirchertach O'Brien

King of Munster, and ruler of Dublin (1074-1086).

1090 - 1121

Domnall macArdgar O'Lochlainn O'Néill

Cenél Ailech.

1121 - 1135

Toirrdelbach macRuaidrí na Saide Buide ua Conchobair / Turlogh

King of Connacht (1106-1156).

1141 - 1150

Toirrdelbach macRuaidrí na Saide Buide ua Conchobair / Turlogh

King of Connacht (1106-1156).

1150 - 1166

Muirchertach macNéill macLochlainn / Murtagh

Cenél Ailech (1136-1166).

1166 - 1175

Ruaidrí macToirrdelbaig

King of Connacht (1156-1183).

1166 - 1170

The kingdom of Leinster is under the direct control of Ruaidrí macToirrdelbaig after Dermot Mac Murrough is forcibly ejected. He gathers support from Normandy and the English king, Henry II, and returns to Ireland with a Norman army. His throne is quickly regained in 1170.


Richard de Clare, earl of Pembroke, or Strongbow, becomes king of Leinster upon the death of Dermot Mac Murrough. This development of Norman lords taking control of Irish kingdoms without being under the authority of the king concerns Henry II of England so much that he arrives to take personal control of what is becoming the invasion of Ireland. He is the first king of England to set foot on Irish shores, arriving with a huge army of 400 ships, 4,000 soldiers, and 5,000 knights. In the event it is a bloodless invasion. The Irish kings know that it is pointless to resist such a vast force. Henry leaves a representative in Ireland to ensure his control and a new colonial mentality is born amongst the Normans. Gerald of Wales subsequently portrays the Irish as being backward and barbaric, ignorant of Christ and of civilisation, thereby justifying the colonisation of Ireland.

1175 - 1258

In 1175, the native high kingship of Ireland is ended when Henry II of England styles himself 'Lord of Ireland'. He hands the title to his son, John, as governor of Ireland. When John becomes king of England in 1199 the control of Ireland is held directly by the crown.

1258 - 1260

Brian Catha an Duin

1260 - 1315

English rule is restored.

In 1315, the forces of Robert the Bruce of Scotland invade Ireland, having offered assistance to King Donal O'Neil of Tyrone and been accepted. The following year, this second front in the Scottish wars against England witnesses Edward de Bruce, brother of Robert, being inaugurated as high king of Ireland, increasing the pressure on the English. The Bruce family have direct maternal links to Brian Boru of the early eleventh century and are therefore valid candidates to rule Ireland as well.

1316 - 1318

Edward de Bruce

Brother of Robert the Bruce of Scotland.


The Scottish campaign in Ireland is initially successful, but the Irish kings outside Ulster are not won over. The attempt peters out and is terminated when Edward is killed at the Battle of Faughart. English rule in Ireland is restored, with the benefit that the end of the war brings an end to destruction and famine.


Henry VIII of England raised Ireland from a lordship to a kingdom and assumes the title 'King of Ireland'.

1579 - 1583

The Second Desmond Rebellion against England is put down.

1594 - 1603

The Nine Years' War between England and Irish rebel Hugh O'Neill ends with the surrender of the Irish.


One of the leaders of the English Parliament, Oliver Cromwell, supports the execution of the Stuart king in January 1649, and leads an army to crush the Irish in August of the same year.


The United Irishmen rebel against British rule in Ireland, but despite French help they are defeated.


The Act of Union joins Ireland with Britain.


A Home Rule for Ireland Bill is passed in Parliament, but immediately suspended upon the outbreak of the First World War.

1916 - 1919

The Easter Rising in Dublin and a declaration of an Irish Republic in 1916 leads to the proclamation being ratified by the self-declared Irish Parliament in 1918. The following year, the parliament is declared illegal by the British government and both the IRA and Sinn Fein are banned.

1921 - 1922

The British government legislates to establish Ireland as an autonomous region of the United Kingdom, terming the twenty-six counties of the south, appropriately, as Southern Ireland. Irish nationalist leader Michael Collins supports the move, but Irish Republican Army support is split, and a civil war erupts in Ireland.


Following the Anglo-Irish Agreement, the Irish Free State is established as a dominion in the British Commonwealth. Irish nationalist leader Michael Collins, head of the Irish Free State, is killed by militant Republicans.


The Irish Free State is abolished and a state which is called simply Ireland comes into being with a new constitution on 29 December, although it is still represented internationally by the British monarchy as an instrument of Irish policy.


The Republic of Ireland is declared with a president at its head, but the six protestant counties of Northern Ireland remain part of Britain.