O'Neill, Flaherty, Lord of Aileach,
on the shores of Lough Swilly, was the first prominent member of
the O'Neill family whose name appears in history, ruling his territory
from 1004 to 1036. O'Donovan, cited by O'Mahony, says: "The
Ui Neill, or the descendants of the monarch Niall of the Nine Hostages,
were divided into two great branches, namely, the southern and northern.
The southern Ui Neill were kings of Meath, and many
of them monarchs of Ireland. The northern Ui Neill, of which there
were two great branches, namely, the race of Eogan, princes of Tyrone,
and the race of Conel, princes of Tirconnell, also furnished many
monarchs of Ireland; but the descendants of Eogan were the most
celebrated of all Milesian clans; of them a great many were kings
of Ulster, and sixteen were monarchs of Ireland.
The race of Eogan took the name of O'Neill in the
10th century, from Nial Ghmdubh (Black Knee), who was killed in
a great battle with the Danes, near Dublin, A.D. 919. The elder
branch of the O'Neill took the name of O'Lochlainn, and MacLoughlin,
from Lochlainn, one of their ancient chiefs.
The O'Neills afterwards recovered the supremacy, and
made a distinguished figure in Irish history, down to the 17th century,
as princes of Tyrone and kings of Ulster. The O'Neills had their
chief seat at Dungannon, and were inaugurated as princes of Tyrone
at Tullaghoge palace, between Grange and Donaghenry, in the parish
of Desertcreight, barony of Dungannon, where a rude seat of large
stones served them as a coronation chair."
The Four Masters record fourteen plundering expeditions
led by Flaherty into different parts of Ireland, both against his
countrymen and the Northmen. He is sometimes called "Flaithbheartach
an Trostain" (Flaherty of the Pilgrim's Staff), from a pilgrimage
he made to Rome. He was slain in 1036.