O'Neill Name Study - Eoghan Mac Niall line

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Surnames/tags: O_Neill O_Neill_Dynasty Irish_roots
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Welcome to the O'Neill Name Study


Project Purpose

The purpose of this project is to show the patrilineal descent of the O'Neill Dynasty (the Irish Royal House of O'Neill, which was taken over and disbanded by King Henry VIII) from the progenitor of the Ui Neill, "Niall of the Nine Hostages -to- Niall Glundubh Mac Aedo, High King of Ireland, King of the Cenél nEógain - to Conn Bacach Mac Cuinn O'Neill, the last King of Tyrone, and his descendants. Further lineage will be explored when this line is complete.

Origin of the O'Neill Surname

"Ó NÉILL - Derivatives: O'Neill, O'Neal, Neill, Neale - A name given to some descendants of Niall Noigiallach, also known as "Niall of the Nine Hostages." It is the surname of several distinct families in different parts of Ireland, of which several clans and family groups are descended. [1]

Eoghan Mac Niall, son of Niall Noígiallach, was progenitor of the Kingdom of Cenél Eógain.

"Niall Glúndub mac Áedo (modern spelling: Niall Glúndubh mac Aodha) was a 10th-century Irish king of the Cenél Eógain and High King of Ireland. He was the 170th Monarch of Ireland and reigned for three years. While many Irish kin groups were members of the Uí Néill and traced their descent from Niall Noígiallach, the O'Neill dynasty took its name from Niall Glúndub rather than the earlier Niall."

It is from this Monarch the surname O'Neill or "Clan-na-Neil," Neilson, Nelson and Nilson are derived, as well as the Clan O'Neill.[1] [2][3]

Prior to this, the names were still expressed in a patrilineal manner as in Gaelic tradition. Niall's grandsons Flaithbertach mac Muirchertach O'Neill and Domhnall Mac Muirchertach O'Neill are believed to be the first of this direct line to use O'Neill as a surname, to distinguish the familial line as descent from Niall Glundubh. [1]

Early Kingdoms: The Uí Neill High Kings of Ireland - The Uí Neill was the designation of those claiming descent from Niall of the Nine Hostages. The list below shows the reigning Kings in order of succession and does not necessarily fall along patrilineal descent. This list is not covered under the name study.

Cenél Eóghain Sovereigns of Ireland Niall Eochaid - "Niall of the Nine Hostages" - eponymous ancestor of the Cenél Eóghain.

Approx 465, Eoghan Mac Niall, son of Niall Eochaid,
504 to 527, Muircheartach Mac Muireadhach, son of Muireadhach Mac Eoghan,
559 to 561, Domhnall and Fearghus, the two sons of Muircheartach, son of Muireadhach
562 to 563, Eochaidh, son of Domhnall; and Baedan Brighi, son of Muircheartach, son of Muireadhach (Cenel Mac Earca).
595 to 600, Colman Rimidh, son of Baedan Brighi, son of Muircheartach.
601 to 607, Aedh Uairidhnach, son of Domhnall Ilchealgach, son of Muircheartach.
709 to 718, Fergal, son of Maelduin,
730 to 738, Aedh Allan, son of Fergal, son of Maelduin
759 to 765, Niall Frossach, son of Fergal, son of Maelduin
793 to 817, Aedh Oirdnidhe, son of Niall Frossach, son of Fergal.
832 to 844, Niall Caille, son of Aedh Oirdnidhe, son of Niall Frosach.
861 to 876,Aedh Finnliath Mac Niall, son of Niall Caille, son of Aedh Oirdnidhe. [4]
Our project starts here with Niall Glúndubh mac Áedo, son of Aedh Finnliath Mac Niall.

Lineage From Niall Eochaid to Niall Glundubh

In progress

Lineage From Niall Glúndubh mac Aedo to Conn Bacach Mac Cuinn O'Neill

WORK IN PROGRESS! This line is in patrilineal descent - generation removed from Niall Glundubh is indicated before name.

Niall Glúndubh mac Áedo - High King of Ireland, King of the Cenél nEógain, son of Aedh Finnliath Mac Niall

1. Muirchertach mac Néill (abt. 0911 - 0943) - King of Ailech (son of Niall Glundubh)
2. Domnall mac Muircheartach Ó Néill, High King of Ireland -son of Muirchertach - Domnall was passed over for the succession upon Donnchad Donn's death the year after Muirchertach's, but eventually became High King following the death of Donnchad's successor Congalach Cnogba in 956." [5]
2. Flaithbertach mac Muirchertach O'Neill (abt 977 - bef. 1036) - King of Aliech, abdicated in 1030 - son of Muirchertach - "Following Flaithbertach's death, his descendants were for seven generations excluded from the kingship of Ailech by the Mac Lochlainn and other branches of the kindred. His eighth-generation descendant Aedh in Macaemh Toinleasg finally receiving a share in the kingship when Ruaidri Ua Conchobair divided Cenél nEógain between the Mac Lochlainn and the Ua Néill in 1167." [6]
3. Aodh Athlamh O'Neill - son of Flaithbertach
4. Aodh Anrachan O'Neill - son of Aodh Athlamh
4. Donal O'Neill - son of Aodh Athlamh
5. Flathartach O'Neill - son of Donal O'Neill
6. Conchobar O'Neill - son of Flathartach
7. Teige Glinne O'Neill - son of Conchobar
8. Conn O'Neill - son of Tiege
8. Mortogh Maighe O'Neill - son of Tiege
9. Aedh Macaemh Toinleasg O'Neill - King of Cenel Eoghain, son of Mortogh
10. Murcertac O'Neill - son of Aedh Macaemh
10. Niall "Ruadh" O'Neill- son of Aedh Macaemh - Niall Ruadh (red-haired Niall) was a Prince of Ulster; died in 1226.
11. Brian Catha an Duin O'Neill - "Brian Catha an Duin O'Neill BrianCatha, also known as Brian Roe, served as Taoiseach of Tyrone. He married Sisile (Cecilia), daughter of Domhnall Mac Lochlin, whose clan Brian had helped subdue. BrianCatha was offered the High Kingship of Ireland by Hugh, the son of Felim O'Connor, of Connaught, Teige O'Brien of Thomond and probably many other chieftains whom he had met at Caol Uisee (Narrow Water) on the Erne in 1258, with their respective forces. Brian accepted and became the 184th Ard Ri, or High King, of Ireland. After he became High King, he, along with the forces of O'Connor, turned his Army against the English invaders. BrianCatha and many other Irish chieftains and men totalling 352 in all were slain in 1260 by the English at Druim-Dearg near Downpatrick in Co. Down." [7]
12. Domhnall O'Neill - son of Brian - adopted the title "The O'Neill." He ruled on three occasions in Tyrone (Tir Owen), viz., 1283-86, 1290-91, and 1295-1325. He was at odds with the English and supported Aodh Buidhe and Neil Culanach O'Neill. Domhnall was summond by Edward I, King of England, in 1302 to fight against the Scots. [7]

Lineage from Conn Bacach to Binkley-335


  • Brian is the son of Conn Bacach mac Cuinn O'Neill
  • Shane is the son of Brian McPhelim O'Neill
  • Phelim is the son of Shane McBrian O'Neill
  • Brian is the son of Phelim Dubh O'Neill
  • Hugh is the son of Brian Mac Phelim O'Neill
  • William is the son of Hugh O'Neall
  • Thomas is the son of William O'Neall
  • Robert is the son of Thomas Henry O'Neall
  • Martha is the daughter of Robert Evans O'Neall
  • James is the son of Martha Jane (O'Neall) Atwood
  • John is the son of James Pervine Atwood
  • James is the son of John Pervine Atwood
  • Esther is the daughter of James Lincoln Atwood
  • Toni is the daughter of [private mother]
  • Summer is the daughter of Toni Gayle (Sain) Barnes

Favorite Sources

MEDIEVAL LANDS: A prosopography of medieval European noble and royal families by Charles Cawley © Foundation for Medieval Genealogy & Charles Cawley 2000-2017.


  1. 1.0 1.1 1.2 Library of Ireland
  2. O'Neill Clan
  3. Wikipedia, Niall Glundubh
  4. http://www.rootsweb.ancestry.com/~irlkik/ihm/uinkings.htm
  5. https://en.wikipedia.org/wiki/Muirchertach_mac_N%C3%A9ill
  6. http://www.oneillclans.com/history/ancient-origins/114-famous-oneills-flaithbertach-an-trostain-qof-the-pilgrims-staffq-king-of-ailech-1004-30-a-1033.html
  7. 7.0 7.1 Desmond O'Neill, The Ancient and Royal Family of O'Neill, O'Meath, Ireland (1995)

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An intriguing reading here. Thanks for sharing!
posted by Roni Lepore
This is looking good Summer!