History Files

Please help the History Files

Contributed: 175

Target: 400

Totals slider

The History Files still needs your help. As a non-profit site, it is only able to support such a vast and ever-growing collection of information with your help, and this year your help is needed more than ever. Please make a donation so that we can continue to provide highly detailed historical research on a fully secure site. Your help really is appreciated.

Gaelic British Isles & Ireland

Tribes and States of Ireland


Kings of Uí Failghe / Offaly (Gaels of Ireland)

This Gaelic kingdom apparently formed from tribal origins in Ireland's midlands region. Ireland was never politically united enough to translate its religious and cultural influence into political power, so its rival kingdoms waxed and waned both in terms of power and territory. Uí Failghe was never more than a minor territory, initially of Laigin, and then a minor kingdom in its own right. Even so, it does seem to have maintained an air of relative independence, fighting off attempts at dominance by the Eóganachta of Munster to the south, while also repelling attempts at conquest by the Uí Neill kings of Mide to the immediate north.

The kingdom's traditional capital was Rathangan in the modern County Kildare, which translates from the Gaelic original as the 'fort of Iomghain'. It was founded between AD 600-700, during the kingdom's early historical period. Today the rath sits a little to the north-west of the modern town of the same name. Iomgain means 'wonder, vulnerator'. There may have been several people of that name in ancient Ireland, but the relationship between the name and the Uí Failghe kings is uncertain.

The name Uí Failghe was gradually Anglicised (or mangled) as Offaly by the Anglo-Norman elite who assumed control large areas of eastern Ireland from the twelfth century onwards. The 'f' would have been a 'v' in prehistory and before that a 'w' sound (the Roman 'v') in common Celtic. The '-ghe' suffix is less clear, possibly a form of '-ig' and/or '-/ic'? If the latter, then Wallic (equivalent to 'Welsh', 'Gallish') may be the name's oldest form. Today the kingdom's ancient borders are partially mirrored in the modern County Offaly, but the kingdom itself was about four times the size of the county.

(Information by Peter Kessler and Edward Dawson, with additional information by Laurence Fullam, from An Etymological Dictionary of the Gaelic Language, Alexander MacBain (1982), from Ireland Before the Vikings, Gearoid Mac Niocaill (1972), from A New History of Ireland, Volume IX, T W Moody, F X Martin, & F J Byrne (Eds, Oxford University Press, 1984), and from External Links: English-Old Gaelic Dictionary, and History of the Catholic Church, and the Book of Leinster, and St Piran Trust, and Bunscoil Bhríde.)

c.113 - 116?

Rus Failge, son of the high king of Ireland, Cathair Mór, may be associated with the founding of a tribal kingdom of Uí Failghe, although this is far from certain. Only the name serves as a connection, while the first historically-known king (or at least, semi-historically-known), Failge Berraide, is a rather mysterious figure.

Shown here are the remains of the fort of Iomghain - early capital of the Uí Failghe - which lies just north-west of the modern town of Rathangan, which itself is a mangling of the ancient name

The Book of Leinster names one Failge Rot mac Cathair as an early king here, which is close enough to Rus Failge and his father's name to provide a possible link. The early Irish poem, Timna Cathaír Máir (The Testament of Cathair Mór) says that Rus Failge is granted the kingdom in succession to his father, so the assumption has to be that Cathair Mór holds the kingship of Uí Failghe, and his son succeeds him. This would seem to establish an early tribal kingdom towards the end of Ireland's legendary period (the apparent misalignment of dates is not a serious concern as those of the legendary period can be very flexible if need be).

fl 116

Rus Failge

Legendary son of High King Cathair Mór. Failge Berraide?

c.116 - 136?

Events late in Ireland's legendary period involve the territory of the Uí Failghe, although no actual kings of the Uí Failghe are mentioned. This makes it highly likely that, if a tribal kingdom does not already exist, the events are being written down much later and are using contemporary names to describe past or legendary events. Following his seizure of Munster and expelling the previous kings, Mug Neit attacks High King Conn Cétchathach (from AD 116). The high king defeats him in two battles in the territory of the Uí Failghe (partially within the modern County Offaly and its immediate surrounding territory) and he is killed. The former kings of Munster are restored to their position.

5th century?

The Laigin interest in Tara, the seat of the high kings of Ireland, probably becomes a thing of the past when the Southern Uí Neill clan (whose northern kin are beginning to advance on the borders of Ulaid) take over the area known as Brega in which Tara lies, probably in this century. In doing this they apparently push back the old Leinster descent-named tribe known as the Laigin to the area south of the River Liffey, and separate them from their kin the Uí Failghe.

The leader of this advance seems to be Coirpre mac Néill, claimed as high king during the late middle fifth century and son of one of the most famous high kings, Niall Noígillach of the Nine Hostages. The heart of this new territory eventually becomes known as Mide, although it is not a single kingdom. In fact, it seems to operate on the same basis as Ireland as a whole, with various local minor kingdoms and an acknowledged (or otherwise) high king at Tara. Immediately to the west of this advance, the Uí Failghe may already feel threatened.

fl 507 - 514

Failge Berraide

First king known to history. Possibly a dynasty founder.

507 - 514

Failge Berraide opposes Fiachu mac Néill, son of Niall Noígillach of the Northern Uí Neill and king of Uisnech in Mide. Fiachu is defeated by Failge at the Battle of Frémainn (Frewin Hill, near Mullingar in the modern County Westmeath). This could be seen as a first advance towards Uí Failghe territory by the Uí Neill of Uisnech, and the rebuff only encourages another attack. Fiachu had apparently received a prophecy that he would win this battle and in 514 he determines to fulfil the prophecy by defeating Failge at the Battle of Druim Derg. This gains him the plain of Mide from the Laigin, as well as the territory between Birr and Uisnech in County Westmeath.

early 6th cent AD

St Piran is the patron saint of tin-miners, and is generally regarded as the national saint of Cornwall. While the saint's origins are open to debate, it is generally accepted that he is St Ciarán of Saigir who had been born and raised on the island of Cape Clear off County Cork in Ireland. His parents are Lughaidh and Liedania (father and mother respectively). After studying scriptures in Rome, he returns to Ireland to be made bishop at his monastic settlement of Saighir Kieran in the territory of the Uí Failghe. There is no reference to his death but St Piran is best known for landing on Perran Beach in Cornwall in the early sixth century and building the tiny St Piran's Oratory on Penhale Sands near Perranporth.

St Piran's Oratory, Cornwall
The 2014 project to unveil the 1500 year-old St Piran's Oratory in Cornwall included long-term conservation work and a plan to ensure that the remains would be displayed to the public, although the work is ongoing


No further mention is made of Failge Berraide, and the fate of the Uí Failghe following their defeat of 514 is unknown. Given the potential scale of the defeat, the tribe or kingdom could be dominated from Uisnech for much of the century before establishing (or having appointed for them) a line of minor native kings. The list of these early kings between the sixth and ninth centuries records their dates of death alone - no reignal dates are included. A date of death is normally a good indication of the end of a reign, although this is not always the case.

? - 579

Bruidge mac Nath Í

Grandson of Failge Berraide.


The first of the established line of kings is Bruidge mac Nath Í (shown inaccurately in the Book of Leinster as Bruigdi mac Cathair). How he comes to be king is unknown, as is the question of whether the Uisnech kings have dominated here until now, and whether they continue to dominate. All that is known is that Bruidge dies in this year (so say the Annals of Ulster), possibly in battle against the Uí Neill. His son, Cathal mac Bruidgi, is not mentioned in the king list, so perhaps he is also dead.

? - 604

Áed Rón mac Cathail

Grandson. Son of Cathal mac Bruidgi.


Possibly it is Uí Failghe's recent history with the kings of Uisnech that informs the king's choice. During the feud amongst the Southern Uí Neill, Áed Rón mac Cathail sides with the Síl nÁedo Sláine branch in their fight against the Clann Cholmáin. Unfortunately he his slain along with Aed Sláine, king of Uisnech, whilst opposing Conall Guthbinn (who dies in 635) and the Clann Cholmáin.

? - 639

Ailill mac Áedo Róin



Relationship unknown. Not shown in genealogies.

fl c.639?

Conaing is known only by his name. The genealogies in the Book of Leinster show Ailill mac Áedo Róin being succeeded by Cillíne mac Forannáin, but the genealogies contain a poem which mentions the royal fort of Rathangan (in the modern County Kildare) and also places Conaing as king between these other two kings. There is no hint of who he may be, so two relatively safe conclusions could be drawn: that he is a usurper who has ended one line of kings and is replaced by a junior branch of kings in the form of Cillíne, great-grandson of Máel Uma; or that he is an unpopular or illegitimate son of Ailill who is removed from the throne and excised from official king lists.

? - 652

Cillíne mac Forannáin

Great-grandson of Máel Uma, brother of Áed Róin. Killed.


Internal strife hits the Uí Failghe. Cillíne mac Forannáin is killed at the Battle of Cúil Corra. Again an otherwise unknown king succeeds him, one Máel Dúin (according to the Annals of Ulster). His reign may be short, which marks him as a potential opportunist who has no legitimate claim to power, and he is eventually replaced by Fland Dá Chongal (who himself is not mentioned in the annals but is mentioned in genealogies).

Fland's position in the list is somewhat speculative, but is the best fit given the subsequent reigns of his many sons. Together they form the Uí Flaind. In addition, with the mother of a couple of those sons being Érenach, daughter of Murchad Midi, king of Uisnech from 689, it is possible that their dominance heralds a scaling back of the traditional enmity against the Southern Uí Neill.

652 - ?

Máel Dúin

Relationship unknown. Not shown in genealogies.

697? - 711?

Fland Dá Chongal / Flann Ua Congaile

Nephew of Cillíne mac Forannáin. Reigned 14 years.

711? - 714?

Forbassach Ua Congaile

Reigned for 3 years (Book of Leinster). Died 714.

? - 741

Ailill Corrach mac Flainn

Son of Fland Dá Chongal. First of many Uí Flaind kings. Killed.


The Battle of Áth Senaig takes place, with the men of Laigin being crushed by the high king of Ireland, Áed Allán. As Laigin men themselves, the warriors of Uí Failghe naturally fight on the side of their eastern kin. Unfortunately four of the many sons of Fland Dá Chongal are killed during the disastrous outcome.

Irish warriors
This modern illustration shows typical Irish warriors between the seventh and tenth centuries AD, with the average foot soldier wearing little (centre), while kings and sub-kings (the next figure to the right) looked very lordly in their Gaelic finery, and mounted warriors from the ninth and tenth centuries were influenced by their Viking enemies, wearing more clothing than had their ancestors

? - 755

Flaithnia mac Flainn


? - 757

Cummascach mac Flainn

Half-brother. Killed.


Cummascach mac Flainn is given a reign of ten years by the Book of Leinster. This may seem to conflict with the two year period following the death of his predecessor and half-brother, but in actuality all of the brothers may be counted as 'reigning' while they provide leadership to the tribal kingdom, while only one of them at any time can be counted as the king of the Uí Failghe. Cummascach meets his own end at the hands of Máel Dúin mac Áedo, who is claimed by the Annals of Tigernach as a king of Munster (although that claim is open to doubt).

? - 770

Cináed mac Flainn

Brother. Killed.


Seeing that the high king of Laigin, Cellach mac Dúnchada, is in trouble following attacks launched against him by the Southern Uí Neill, Cináed mac Flainn also challenges Cellach's authority. Unfortunately, Cellach is still powerful enough to slay Cináed at the Battle of Áth Orc in Uí Failghe territory. This conflict would seem to suggest that the Uí Failghe no longer look upon the Laigin as close kin.

? - 782

Mugrón mac Flainn

Brother. Killed at the Battle of Curragh.

? - 783

Domnall mac Flaíthnia

Son of Flaithnia mac Flainn. Captured and later killed.

? - 803

Óengus mac Mugróin

Son of Mugrón mac Flainn. Killed.


Fínsnechta Cethardec mac Cellaig, over-king of the Laigin, is keen on ensuring his dominance over the church of Kildare. In a way which remains unexplained, this leads to conflict with the Uí Failghe. Óengus is killed through treachery by the followers of Fínsnechta Cethardec. His successor and cousin, Flaíthnia mac Cináeda, is also assassinated just three years later, probably also on the orders of Fínsnechta Cethardec. The Book of Leinster gives Flaíthnia a reign of two years, which is not incompatible with a reign of 803-806 if it begins at the end of 803 and ends at the start of 806.

 ? - 806

Flaíthnia mac Cináeda

Son of Cináed mac Flainn. Killed.

? - 829

Cináed mac Mugróin

Brother of Óengus mac Mugróin. Founder of the Clann Cináeda.

? - 842

Mugrón mac Óengusa

Son of Óengus mac Mugróin.

? - 849

Niall mac Cináeda

Son of Cináed mac Mugróin.

? - 881

Máel Sinchill mac Mugróin

Grandson of Óengus mac Mugróin.

? - 891

Conchobar mac Flannacáin

? - 897

Uathmarán mac Conchobair



The Uí Failghe and their kings sink into a period of obscurity at this point. The reasons are unknown but could be related to the recent wave of Viking attacks in Ireland from their various east coast bases such as the one at Dublin.

Vikings in combat
This may be a fairly typical image of Vikings staging a raid - whether in Ireland or Britain the scene would have been very much the same - but they seem to be faced with some well-armed opposition on the shore


Re-emerging from a century and-a-half of obscurity, the kings of Uí Failghe have, recently it seems, adopted the clan name of Ua Conchobair Failghe, although they bear no relationship to the powerful Ua Conchobair kings of Connacht. In later years this is simplified as Ó Connor Faly, possibly thanks to Norman influence.

? - 1051

Congalach Ua Conchobair

Died 1051.

1051 - 1071

Gilla Patraic mac Conchobair Ua Sibleain

1071 - 1115

Conchobar mac Congalaig

Joint king of Laigin. Killed by the Vikings of Dublin.

? - 1095


Joint king?


Donnchad mac Murchada, king of Laigin, and Conchobar mac Congalaig (also referred to as Conchobar Ua Conchobair Failge) see an opportunity to make the most of the faltering power of Munster - under the power of the Uí Briain. The pair launch an attack on Dublin, whose defending forces are led by Domnall mac Muirchertaig ua Briain (Domnall Gerrlámhach) of the Uí Briain (dies 1135). The attempted invasion is defeated and both kings are killed, but Donnchad's successor is soon able to seize Dublin for Laigin.

1115 - c.1118

Rogan mac Domnaill meic Conchobair

Son of Domnaill.


With the death of Diarmait mac Énna meic Murchada of Laigin in Dublin, his successor and kinsman, Enna, is expelled by Domnall mac Muirchertaig ua Briain (Domnall Gerrlámhach). The Uí Briain of Munster now control the stronghold once again.

c.1118 - 1130

Cu Faifne mac Congalaig

Brother of Conchobar.

1130 - 1134

Donnchad mac Con Faifne


1134 - ?

Aed mac Domnaill

Brother of Rogan mac Domnaill.

Mael Morda mac Conchobair

Son of Conchobar.

Conchobair mac Con Faifne

Brother of Donnchad mac Con Faifne.

Mael Sechlainn mac Conchobair

Brother of Mael Morda?

Congalach mac Con Faifne

Brother of Conchobair mac Con Faifne.

Murchad mac Con Faifne


? - c.1151

Muirchertach mac Muirchertaig

Relationship unknown.

c.1151 - 1159

Aed mac Donnchada (Gilla na Findmona)

Son of Donnchad mac Con Faifne. Fled to Connacht 1156-1157.

1156 - 1157

High King Muirchertach mac Lochlainn of Ireland installs his own client king in Mide. Then he evicts the kings of Loígis, Uí Failghe, and Osraige. All three dispossessed kings flee to Connacht. Munster is subdued, although this is quickly reversed by Ruaidrí mac Toirrdelbaig ua Conchobair, king of Connacht.

1159 - 1161

Domnall Ruad mac Congalaig

Son of Conglach mac Con Faifne.

1161 - 1164

Mael Sechlainn mac Congalaig


1164 - ?

Donchad Ruad Roigne

Relationship unknown.

Diarmait mac Congalaig

Son of Conglach mac Con Faifne.

1166 - 1170

King Dermot mac Murrough is forcibly ejected from Laigin by the high king of Ireland. He flees to Bristol and then Normandy where he gains the support of the English king, Henry II, and Norman allies with which to return to Ireland. The main invasion takes place in 1169 at Bannow Bay with the arrival of the first army of Norman mercenaries to enter Ireland, totalling thirty knights, sixty men-at-arms, and three hundred archers under the Fitzgeralds, marcher lords of Wales.

The coming of the Normans to Ireland was a blow for the Irish - the newcomers were tactically and militarily far more powerful than anything seen before by the native kings

Laigin is quickly regained following the Battle of Baginbun. A hundred Normans break 3,000 Irish by driving cattle through them to shatter their formation. Then the better armed and equipped Normans slaughter many of the Irish, and take a large number of prisoners from the rest. The Norman commander, Richard de Clare, earl of Pembroke (nicknamed Strongbow), marries Dermot's daughter and is named his heir.

This coming of the Anglo-Normans also heralds changes within Ui Failghe. Very soon the ancient capital of Rathangan is abandoned in favour of a new seat further west at Daingean. The name in Gaelic is An Daingean, meaning 'the fort', or Daingean Ua bhFáilghe. meaning 'the fort of the Uí Failghe clan'. (Daingean is later established under Queen Mary Tudor as the county town of the newly-formed King's County, named as such for her husband, Philip II of Spain.)

? - 1169?

Muirchertach mac Congalaig


1169? - 1172?


Unknown king or kings.

aft 1172 - 1193

Diarmait mac Con Broga Ua Dimmusaig


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 lordship of Ireland is held directly by the crown in personal union. The king of England is also the king of Ireland.

The arrival of the Vikings in Ireland had begun a process of linguistic transition. The process is now almost certainly hurried along by the Norman takeover of the island's eastern regions. Gaelic names become mangled by their French pronunciation (the same process is also taking place in the English language, already subtly altered by the Danes). Over time Connacht becomes Connaught, Laigin becomes Leinster, Ulaid becomes Ulster, and Mide becomes Meath. Lesser regions or groups also change, such as the Uí Failghe to Offaly, Uí Neill to O'Neill, Ua Conchobair to O'Conner, and so on. The '-ster' endings are Viking.

fl 1212

Muirchertach mac Brian

Of the meic Donnchada (clan).

? - 1225

Mael Morda mac Muirchertaig


1225 - ?

Muirchertach mac Mael Morda



Maurice FitzGerald, second Anglo-Norman lord of Offaly (a territory which neighbours the Uí Failghe kingdom), becomes lord lieutenant of Ireland, the king's representative on the island.

Rosses Point
Maurice FitzGerald met his end at the Battle of Creadran Cille (located at Ros Ceide, modern Rosses Point shown here) within the north-western territory of Connacht, whilst fighting against Tír Chonaill and suffering fatal wounds in single combat, leader against leader

? - c.1305

Muirchertach mac Muirchertaig


1305 - ?

Murchad mac Muirchertaig


? - 1329

Mael Sechlainn mac Muirchertaig


? - 1384

Muirchertach Óg mac Muirchertaig


1384 - 1421

Murchad mac Muircheartaig Óg



The Battle of Cluan Immorrais sees the minor kingdom of Uí Failghe defeat the Galls of Mide.

1421 - c.1425

Diarmaid mac Muirchertaigh Óg



Upon the death of Diarmaid mac Muirchertaigh Óg, the kingdom is inherited by Máireg Béan Ó Conchubhair Fáilghe, daughter of Tadc Ó Céarbhaill of Ely. This ends the domination of the mac Muircherartaig and begins that of the Ó Conchubhair. Máireg is famous as a patron of bardic classes, and her death (of cancer or possibly leprosy - the chronicler in the Annals of Connacht seems confused over which it is) saddens everyone who knows her.

c.1425 - 1451

Máireg Béan Ó Conchubhair Fáilghe

Dau of Tadc Ó Céarbhaill of Ely. Queen of Uí Failghe. Died.

c.1425 - 1458

An Calbhach Mór mac Murchada

Husband and king.


Feidlim mac an Chalbhaig

Son. Died in the same year as his mother.

1458 - 1474

Conn mac an Chalbhaig

Brother of Feidlim.

1474 - 1511

Cathaoir mac Cuinn


1511 - 1517

Brian mac Taidhg meic an Chalbhaigh


1517 - c.1525

An Calbhach mac Taidhg


c.1525 - 1556

Brian mac Cathaoir

Last king. Accepted baronetcy of Offaly in 1535. Died 1550/56?

1534 - 1535

Gerald FitzGerald. earl of Kildare, is Ireland's deputy governor. He is summoned to London and appoints as his deputy his son, Thomas. By July rumours are circulating that Gerald has been imprisoned and that Thomas is next. Thomas takes preventative action by riding to St Mary's Abbey in Dublin, accompanied by 140 horsemen with silk fringes on their helmets (earning him the nickname 'Silken Thomas'). There, he publicly renounces his allegiance to the crown, beginning his rebellion.

Following defeat in Dublin he retreats to his stronghold at Maynooth in County Kildare. This is captured in 1535 by Sir William Skeffington. Thomas is absent at the time, but has over-estimated the support of the Irish people. Eventually he surrenders with a promise of clemency, but he and five uncles are still executed at the Tyburn gallows, on 3 February 1537. One of his supporters is Brian mac Cathaoir, king of Uí Failghe. Brian is pardoned and is granted the resurrected title 'baron of Offaly' as his minor kingdom is reduced in rank.

The kingdom may effectively be at an end but the territory continues to be ruled by its native leaders until the baronetcy is forfeited upon Brian's death in 1550 (although some sources offer the somewhat contradictory date of 1556). The territory is divided by Queen Mary Tudor into a rump county of Offaly or Ophaley (known as King's County until Irish independence), with the other parts going to Kildare and Laois (Queen's County until independence). In 1554 Offaly is handed to Gerald FitzGerald of the neighbouring County Kildare (half-brother of the traitorous Thomas FitzGerald) and now earl of Kildare in his own right. The title lapses in 1599 when Gerald's line dies out, although the senior title of Kildare is passed to a cousin. The baronetcy of Offaly is recreated in 1620 and survives to this day.

Images and text copyright © all contributors mentioned on this page. An original king list page for the History Files.