About 1700 years B.C., Milesius, then king of Spain, planned an invasion of Ireland. He died, however, before he could carry out his plan but his two sons, Eber and Eremon, saw it through. They disagreed, however, as to which of them should rule and finally settled the argument by dividing the country between them. This did not seem to be satisfactory as Eber was later killed by his brother. Thus, Eremon became king of all Ireland.
Niall of the Nine Hostages (Nial Naoi nGiallach) who reigned from 379-405 A.D. and is reputed as having brought St. Patrick to Ireland as a slave boy, was the 52nd lineal descendant of Eremon.
Niall had many sons among whom was Eoghan, ancestor of the O’Neills (Cineal Eoghain) and Conall, ancestor of the O’Donnells (Cineal Chonaill).
Conall asserted his dominance over that territory which became known as ‘Tír Chonaill’ (approx. Co. Donegal minus Inishown). Among Conall’s descendants were no fewer than 41 Saints, 10 High Kings and a host of lesser nobility.
Around the year 1000 A.D. Brian Boru, then High King, ordered that families take surnames. The practice before that was for a person to add the name of his father or grandfather to that of his own, a practice which still exists in some parts of Ireland today.
The change was gradual and it was not until a century later that the surname ‘Ó Domhnaill’ (O’Donnell) appeared when Cathbharr (d. 1106) adopted the name of his ancestor - Domhnall Mór- as his surname. (There is an entry in the Annals of the Four Masters for the year 1010 that reads - ‘Maelruanaidh Ua Domhnaill, lord of Cinel Luighdheach, was slain by the men of Magh Ith.’ But this not officially accepted as a surname.)
Another clan in the Clare/Tipperary area adopted the same surname but from a different ancestor, of course. This was long before Cineal Chonaill did and sometimes causes confusion and misunderstandings. It is difficult to tell whether a southern O’Donnell is a descendant of the Clare/Tipperary clan or a northern O’Donnell who ‘lost his way’ on his journey to or from Kinsale, although DNA testing should go along way to show the difference.
About the year 1200A.D. Eighneachan was inaugurated as the first ‘Ó Domhnaill’ (Chief of the O’Donnells). Twenty five others were to follow; ending with Niall Garbh in 1603. The inauguration ceremony, which took place at Kilmacrennan, had both a lay and a religious side to it.
The O’Donnells first lived along the Lennon River. They had a lake dwelling or Crannóg in Lough Gartan and, later, their first permanent home at Ramelton. Later still, they established themselves at Murvagh on the Erne. At the beginning of the 15th century they built a castle at Ballyshannon and 50 years later built one in Donegal Town. The latter lay in ruins for a few centuries but was restored towards the end of the 20th century. Today it is a thriving visitor centre.
The prominent role played by this royal family in their country’s history is well recorded but after their overthrow by the English and the collapse of the old Gaelic order in 1602 (Battle of Kinsale) less is known of them.
The main family immigrated to the Continent in 1607 (Flight of the Earls) where all were to die within a short period of time - the last dying in 1642. Other branches of the family were moved to Connaught during the Cromwellian plantations. About the middle of the 18th century some of these immigrated to Spain and Austria, in which countries they and their descendants were to play an important role.
The most senior O’Donnell family today (according to the office of the Chief Herald) is that of John O’Donel (deceased), Blackrock, Co. Dublin, namely Fr. Hugh O.F.M., Nuala and Siobhan. Thus Fr. Hugh, a Franciscan Friar, at present based in Killiney, is head of the O’Donnells. Next in seniority is Hugo O’Donnell, Duke de Tetuan, Madrid, Spain. The next in line, Douglas Count O’Donell von Tyrconnell, lives near Salzburg in Austria.
There are, undoubtedly, other descendants of the noble house of Tyrconnell but absence of proof prevents their genealogy from being determined.