Máel Sechnaill mac Máele Ruanaid, who had died November 20, 862, was on that occasion described in the Annals of Ulster as ri h-Erenn uile, king of all Ireland.

This title will never be used for Áed Findliath, king of Ailech, even though he assumes the kingship of Tara following Máel Sechnaill's death, and has also been counted in the lists of High Kings of Ireland.

His kingship will be disputed throughout his seventeen year-long reign, and he does not even have support from the southern clans of Uí Néill.

The annals show that the Taillten Fair on was not held in six of those seventeen years, which is a strong indication of strife and unrest.

The Norse Dublin had, by the beginning of Áed's reign, become an important, if not very trustworthy, ally in the struggle for power in Meath.

Máel Sechnaill's successor as head of Clann Cholmain and king of Meath, Lorcán mac Cathail, had allied himself with Amlaib, Ímar and Auisle against Flann of Brega, a former ally of Dublin, who had remained Áed's most important ally in the central part of Ireland.

Lorcán and his Norse allies had plundered Brega in 863, and in 864 Conchobar mac Donnchada, king of Lagore (southern Brega) and presumably an ally of Flann against Lorcán, had been captured and drowned near Clonard on Amlaibhs order.

Áed had led an host to Míde, captured Lorcán, and blinded him.

Áed has had some notable victories against the Norse, but the main reason for his success is probably neither that he was a military genius or a particularly gifted politician.

He had defeated the Vikings at Lough Foyle in 866 and uprooted their settlements.

Amlaíb and Auslie had left Ireland in 866 with the larger part of the Norse forces, and in cooperation with the Norse-Gaels from present day Scotland they had attacked the Picts.

Áed had seized this opportunity, plundering and burning all the Norse bases (longphorts) in the northern part of Ireland.

Áed in 868 had again been confronted by a coalition of his Irish rivals and the Norse-Gaels.

According to the Annals of Ulster, he defeated "the Uí Neíll of Brega, and the Laigin, and a large force of the foreigners" in a battle at a place called Cell Ua nDaigri.

Flann of Brega had been killed in this battle, which will later be presented as a decisive victory over the Norse.

Amlaibh and Ímar are, however, very active in Ireland during the following years and do not in any way seem to be seriously weakened, neither in ambition nor in strength.

It is probably more accurate to regard this battle as a victory over the southern Uí Neíll and Leinster.

Áed in 870 had followed up his victory by invading Leinster with the support of his new ally Cerball of Osraige, and in 874 again invaded Leinster.

Áed Findliath dies on November 20, 879, at Druim Inasclainn in the territory of Conaille.

On this occasion he is described as "king of Tara" (rex Temorie).

He is buried at Armagh.

His first cousin and stepson Flann Sinna, king of Meath from 877, succeeds to the High Kingship of Ireland.