The O'Donnell dynasty ( or Ó Domhnaill, Ó Doṁnaill or Ua Domaill; meaning "descendant of Dónal") were the dominant Irish clan of the kingdom of Tyrconnell in Ulster in the north of medieval and early modern Ireland.O'Cochlain, Rupert S (1950). The O'Donnells of Tirconaill. Journal of the County Donegal Historical Society

Naming conventions

Male Daughter Wife (Long) Wife (Short) Ó Domhnaill Ní Dhomhnaill Bean Uí Dhomhnaill Uí Dhomhnaill Ó Dónaill Ní Dhónaill Bean Uí Dhónaill Uí Dhónaill

Origins Like the family of O'Neill, that of O'Donnell of Tyrconnell was of the Uí Néill, i.e. descended from Niall of the Nine Hostages, High King of Ireland at the beginning of the 5th century; the O'Neill, or Cenél nEógain, tracing their pedigree to Eógan mac Néill, and the O'Donnells, or Cenél Conaill, to Conall Gulban, both sons of Niall. Conall was baptised by St. Patrick.

Arms and motto The Roman Emperor Constantine the Great converted to Christianity after a vision before the famous Battle of the Milvian Bridge, having seen a chi-rho in the sky, and thence the motto In Hoc Signo Vinces, telling him he would be victorious with the sign of the cross. The chi-rho was adopted on a banner, the labarum, upheld on a vexillum, which resembled a Christian cross, and in time the motto became associated with the Cross all over Europe. Legend has it that St. Patrick struck the shield of Conall, son of King Niall of the Nine Hostages, with his crosier, called Bachal Isu (the staff of Jesus) inscribing thereon a sign of the cross and told him the same, and baptized him. According to the Life and Acts of Saint Patrick (chapter 138), commissioned by Sir John de Courcy and written by Jocelyn of Furness (c. 1185 AD), St. Patrick took his staff, known as the staff of Jesus, or Bacall Iosa, and struck the shield of Prince Conall, rendering a sign of the Cross on it, “et mox cum baculo suo, qui baculus Jesu dicebatur Crucis signum ejus scuto impressit, asserens neminem de stirpe ejus in bello vincendum qui signum illud”, and thus indicating that he and his offspring would henceforth be victorious in battle if they followed that signLife and Acts of Saint Patrick, by Jocelyn of Furness (chapter 138)s:The Life and Acts of St. Patrick/Chapter CXXXVIII. This legend is also described several centuries later in the Lebhar Inghine i Dhomhnaill.Lebhar Inghine i Dhomhnaill (The Book of O'Donnell's Daughter), a medieval Gaelic manuscript finished in the early 1600s in the Irish Franciscan College in Louvain, and lodged today in the Bibliotheque Royale in Brussels (Ms reference 6131-3). Examples of the arms registered date back to 1567 at least, when Sir Hugh Dubh O'Donnell was knighted by Sir Henry Sidney (see Genealogical Office Manuscript "Knights Dubbed" no.51, page 115) His land became Tír Chonaill, Tyrconnell, the land of Conall.

Conall's Constantinian shield, and this motto, have been the main O’Donnell armsAn exemplification can be found in those of Rory O'Donnell, 1st Earl of Tyrconnell, in Manuscript 34 of the Genealogical Office under the Chief Herald of Ireland in various forms, through the centuries. The motto also appears prominently placed as a motto on a ribbon unfurled with a passion cross to its left, beneath a window over the Scala Regia, adjacent to Bernini's equestrian statue of Emperor Constantine, in the Vatican. Emperors and other monarchs, having paid respects to the Pope, descended the Scala Regia, and would observe the light shining down through the window, with the motto, reminiscent of Constantine's vision, and be reminded to follow the Cross. They would thence turn right into the atrium of St. Peter's Basilica, ostensibly so inspired. In an earlier version (before Bernini's renovations in the mid-17th century), something similar may have resonated with and been observed by Prince Rory O'Donnell, 1st Earl of Tyrconnell following his visit to Pope Paul V (at the Palazzo Quirinale) in Rome, just prior to his death in 1608. It would certainly have resonated with and been observed by Cardinal Patrick O'Donnell.

Territory Tyrconnell, the territory named after the Cenel Conaill, is the vast territory where the O'Donnells held sway, comprised the greater part of the modern county of Donegal except the peninsula of Inishowen. But it also included areas outside Donegal, such as the baronies of Carbury in County Sligo, Rosclogher in County Leitrim, and Magheraboy and Firlurg in County Fermanagh, and part of southern County Londonderry, hence it straddled the modern Republic of Ireland and also part of Northern Ireland in the UK. The jewel in the O'Donnell crown was Donegal Castle, one of seven O'Donnell castles, and now a national monument restored in the 1990s. Tyrconnell also, therefore, bordered on territory ruled by the O'Neills of Tyrone, who were periodically attempting to assert their claim of supremacy over it, and hence the history of the O'Donnells is, for the most part, a record of clan warfare with their powerful neighbours, and of their own efforts to make good their claims to the overlordship of northern Connacht, and a wider swathe of Ulster. Nonetheless, Tyrconnell existed for a period as an independent kingdom, recognised by King Henry III of England.see Close Roll, in the Tower of London, 28 Hen. 3m.7

Ascendancy Gofraidh Ó Domhnaill, the first chieftain, was son of Domhnall Mór Ó Domhnaill. In 1257, Gofraidh was victorious when he went to battle at Creadran-Cille against Maurice FitzGerald.Cosgrove, Art, ed. (2008). A new history of Ireland (1. publ. in paperb. ed.). Oxford: Oxford University Press. ISBN 9780199539703. Upon Gofraidh's death, subsequent to wounds incurred during the battle against Ó Néill, he was succeeded in the chieftainship by his brother Domhnall Óg, who returned from Scotland in time to withstand successfully the demands of Ó Néill. Over time, the O'Donnell King of Tyrconnell became known as the Fisher-King, on the Continent,O’Domhnaill Abu, Newsletter of the O’Donnell Clan Association, Issue no. 17, page 2 ostensibly due to the export of fish traded for wine in La Rochelle.Simms, Katherine. Late Medieval Donegal, chapter 6 in Donegal History and Society – Interdisciplinary Essays etc. edited by Nolan, Ronayne, & Donleavy, Geography Publications, Dublin, 1995

Patronage by the O'Donnell dynasty The O'Donnells were patrons of the arts, literature, and of religious benefices. In particular, one, Manus, wrote the biography of ColmCille (St. Columba). They also were the patrons of the Franciscans in Donegal Abbey. They also exercised "jus patronus" to nominate bishops.

In the early 14th century A.D., the O'Donnell rulers aided Templar knights fleeing via Sligo and Tyrconnell to Scotland where a Templar priory existed at Ballymote , a Percival family estate for the last 300 years. The Stewarts relied on the O'Donnells in the balance of power with the MacDonalds beginning in the fourteenth century.Egan, Simon. “JAMES IV, THE O’DONNELLS OF TYRCONNELL and the Road to Flodden.” History Ireland, vol. 24, no. 6, 2016, pp. 16–19. JSTOR website Retrieved 30 Mar. 2025.

The O’Donnell rulers of Tyrconnell are also noted for having in the late 12th century given sanctuary to the Donlevy dynasty of Ulaid (Ulster), after their kingdom had fallen to John de Courcy in 1177. It is in Tyrconnell that a branch of the Donlevy's became known as the MacNulty's, deriving from the Irish Mac an Ultaigh, meaning "son of the Ulsterman", in reference to their former kingdom of Ulaid.Rev. Patrick Woulfe, Priest of the Diocese of Limerick, Member of the Council, National Academy of Ireland, Irish Names and Surnames, © 1967 Baltimore: Genealogical Publishing Company, in Irish and English, p. 518, “O’Duįnnsléibe … also known by surname MacDuįnnsléibe … and by their place of origin Ultaċ and Utaċán.”, and, also, at p. 356 “… also Ultaċ and Utaċán, …” and “Cf. Ultaċ and Utaċán.” During the Donlevy exile in Tyrconnell, The O’Donnell gave them the high Gaelic status of “ollahm leighis”A. Nic Donnchadha, “Medical Writing in Irish”, in 2000 Years of Irish Medicine, J.B. Lyons, ed., Dublin, Eirinn Health Care Publications © 2000, p. 217, noting the MacDonlevy as one of the ancient hereditary Irish medical families (Nic Donchadha contribution reprinted from Irish Journal of Medicine, Vol. 169, No. 3, pp 217-220, again, at 217).Susan Wilkinson, “Early Medical Education in Ireland”, Irish Migration Studies in Latin America, Vol. 6, No. 3 (November 2008) pp 157-158, discussing the high status that physicians were accorded in ancient Gaelic society and, specifically, the particularly high status of "ollahm leighis". Wilkinson also alludes that the high status accorded the king’s physician was due in no small part to the fact that many a battle-wounded Gaelic chief owed his life to these skilled physicians and field surgeons, “Every Irish chieftain was accompanied into battle by his personal liaig, and not a few owed their lives – following near-fatal spear or sword injuries – to the skills of their Druid physician.” and, also, at footnote 2 of cite “The word “liaig” means ‘leech’, an archaic term for a doctor or healer. The term is often used for a Druidic doctor in ancient texts.” Leeching (medical) for millennia was in Ireland as elsewhere a commonly employed ancient medical practice. or his official physicians.Edward MacLysaght, The Surnames of Ireland, 5th Edition, Irish Academic Press, Dublin, 1980, p 238, 292, who cites to 2 entries in The Annals of the Four Masters, which is a historical chronicle that records, among other matter, the births and deaths of Gaelic nobility. The first entry cited is an entry recording the 1395 A.D. death of a Maurice, the son of one “Paul Utach”, who is, himself, recorded there to be “Chief Physician of Tyrconnell” and also as “Paul the Ulidian”. It is there in the Annals further stated by its authors of the father Paul Ultach that “This is the present usual Irish name of the Mac Donlevy, who were originally chiefs of Ulidia. The branch of the family who became physicians to O’Donnell are still extant (at the time of compilation of the Annals in the 17th century just after the fall of this last Gaelic sovereignty of Tirchonaill, itself, in 1607), near Kilmacrenan, in the county of Donegal.” The second citation is to an entry recording the 1586 A.D. death of "Owen Utach", who is therein noted to be a particularly distinguished and skilled physician. The Annals compilers further elaborate of Owen Ultach at this entry that “His real name was Donlevy or, Mac Donlevy. He was physician to O’Donnell.”

It was in fact two of these deposed MacDonlevy (> MacNulty) royals and Roman Catholic priests thereto exiled in Tyrconnell, Fathers Muiris Ulltach in full Muiris mac Donnchadh Ulltach Ó Duinnshléibhe and Muiris Ulltach in full Muiris mac Seaán Ulltach Ó Duinnshléibhe, who both along with the Archbishop of Tuam attended Hugh Roe O'Donnell (aka Red Hugh O’Donnell), The O'Donnell of 1601 Kinsale fame, in his exile at his death bed at Simancas Castle in Spain in 1602. And, it was, in turn, an Irish Count O’Donnell, who compassionately married the widow (d. 1708) of Don-Levi, a Jacobite (Jacobitism) and, thereby, on James II of England's and his French allied's failure to reclaim his British crowns, the last The MacDonlevy to sit in Ireland (departed 1691), after this prince died in exile with the Stuarts in France at the Archbishopric of Treves. This union of the MacDonlevy and the O'Donnell, though, bore no issue.John O’Hart, Irish Pedigrees; or, The Origin and Stem of the Irish Nation, 5th edition, in two volumes, originally published in Dublin in 1892, reprinted, Baltimore: Genealogical Publishing Company, 1976, Vol. 1, p. 417