The supremacy was vested in the descendants of Niall N61giallach without interruption until 1002; but as Niall's descendants were represented by four reigning families, the high-kingship passed from one branch to another.
Niall's son, Aedh (Hugh) Finnlaith, was father of Niall Glundubh (i.e.
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 government now sent Sir Henry Docwra to Derry, and O'Donnell entrusted to his cousin Niall Garve the task of opposing him.
His grandson, Niall (791-845), drove back the Vikings who in his time began to infest the coast of Donegal.
Dublin was captured, and the high-king Niall Glundub (910-919) prepared to oppose the invaders.
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 whole kingdom of the north is commonly designated the kingdom of Ailech, from the ancient stronghold near Derry which the sons of Niall probably took over from the earlier inhabitants.
The allegiance of the rulers of Munster to Niall and his descendants can at the best of times only have been nominal.