O'NEILL, the name of an Irish family tracing descent from Niall, king of Ireland early in the 5th century, and known in Irish history and legend as Niall of the Nine Hostages.
The descendants of Niall spread over Ireland and became divided into two main branches, the northern and the southern Hy Neill, to one or other of which nearly all the high-kings (ard-ri) of Ireland from the 5th to the 12th century belonged; the descendants of Eoghan being the chief of the northern Hy Neill.'
Of this monarch, known as Murkertagh MacNeill (Niall), and sometimes by reference to his mother as Murkertagh Mac Erca, the story is told, illustrating an ancient Celtic custom, that in making a league with a tribe in Meath he emphasized the inviolability of the treaty by having it written with the blood of both clans mixed in one vessel.
A lineal descendent of Murkertagh was Niall Frassach (i.e.
His grandson, Niall (791-845), drove back the Vikings who in his time began to infest the coast of Donegal.
Niall's son, Aedh (Hugh) Finnlaith, was father of Niall Glundubh (i.e.
Niall of the black knee), one of the most famous of the early Irish kings, from whom the family surname of the O'Neills was derived.
On the death of Domhnall in 911 Niall Glundubh became king of Ailech, and he then attacked and defeated the king of Dalriada at Glarryford, in County Antrim, and the king of Ulidia near Ballymena.
He was killed in battle against the Norse in 943, and was succeeded as king of Ailech by his son, Donnell Ua Niall (i.e.
O'Neill, grandson of Neill, or Niall, the name O'Neill becoming about this time an hereditary family surname 2), whose grandson, Flaherty, became renowned for piety by going on a pilgrimage to Rome in 1030.
Niall Og O'Neill, one of the four kings of Ireland, accepted knighthood from Richard II.
The latter were possibly taking part in the raid of the Irish king Niall Noigiallach, who met with his end in.
Patrick's activity was bound to bring him sooner or later into conflict with the High-king Loigaire (reigned 428-467), son of Niall Noigiallach.
Like the family of O'Neill, that of O'Donnell was descended from Niall of the Nine Hostages, king of Ireland at the beginning of the 5th century; the O'Neills, or Cinel l Owen, tracing their pedigree to Owen (Eoghan), and the O'Donnells, or Cinel Connell, to Conall Gulban, both sons of Niall.
This was Niall Garve, second son of Calvagh's son Conn.
Niall Garve O'Donnell (1569-1626), who was incensed at the elevation of his cousin Hugh Roe to the chieftainship in 1592, was further alienated when the latter deprived him of his castle of Lifford, and a bitter feud between the two O'Donnells was the result.
Niall Garve made terms with the English government, to whom he rendered valuable service both against the O'Neills and against his cousin.
But in 1601 he quarrelled with the lord deputy, who, though willing to establish Niall Garve in the lordship of Tyrconnel, would not permit him to enforce his supremacy over Cahir O'Dogherty in Inishowen.
After the departure of Hugh Roe from Ireland in 1602, Niall Garve and Hugh Roe's brother Rory went to London, where the privy council endeavoured to arrange the family quarrel, but failed to satisfy Niall.
Charged with complicity in Cahir O'Dogherty's rebellion in 1608, Niall Garve was sent to the Tower of London, where he remained till his death in 1626.
The government now sent Sir Henry Docwra to Derry, and O'Donnell entrusted to his cousin Niall Garve the task of opposing him.
Niall Garve, however, went over to the English, making himself master of O'Donnell's fortresses of Lifford and Donegal.
But the arrangement between Rory and Niall Garve insisted upon by the government was displeasing to both O'Donnells, and Rory, like Hugh Roe before him, entered into negotiations with Spain.