Flann’s last years were disturbed by domestic dissensions.  His sons, Donough and Conor, both rebelled against him; but Nial Glundubh (of the black knee), a northern Hy-Nial chief, led an army against them, and compelled them to give hostages to their father.  Flann died the following year, A.D. 914, and was succeeded by the prince who had so ably defended him.  Meanwhile, the Danes were not idle.  Amlaff[203] has signalized his advent by drowning Conchobhar, “heir apparent of Tara;” by slaying all the chieftains of the Deisi at Cluain-Daimh; by killing the son of Clennfaeladh, King of Muscraighe Breoghain; by smothering Machdaighren in a cave, and by the destruction of Caitill Find (Ketill the White) and his whole garrison.  Oisill is the next chief of importance; and he “succeeded in plundering the greatest part of Ireland.”  It is not recorded how long he was occupied in performing this exploit, but he was eventually slain, and his army cut off, by the men of Erinn.  The deaths of several Danish chieftains occured about this period, and are referred to the vengeance of certain saints, whose shrines they had desecrated.  In A.D. 864 according to the Four Masters, 867 according to O’Flaherty, the Danes were defeated at Lough Foyle, by Hugh Finnliath, King of Ireland.  Soon after, Leinster and Munster were plundered by a Scandinavian chief, named Baraid, who advanced as far as Ciarraighe (Kerry):  “And they left not a cave under ground that they did not explore; and they left nothing, from Limerick to Cork, that they did not ravish.”  What treasures the antiquarian of the nineteenth century must have lost by this marauder!  How great must have been the wealth of the kings and princes of ancient Erinn, when so much remains after so much was taken!  In 877 the Black Gentiles took refuge in Scotland, after suffering a defeat in an engagement with the White Gentiles.  They were, however, consoled by a victory over the men of Alba, in which Constantine, son of Kenneth, was slain, and many others with him.  Their success proved beneficial to Ireland, for we are told that a period of “rest to the men of Erinn” ensued.  The Danes still held their own in Dublin and at Limerick, occasionally plundered the churches, and now and then had a skirmish with the “men of Erinn;” but for forty years the country was free from the foreign fleets, and, therefore, enjoyed a time of comparative quiet.

In the year 913 new fleets arrived.  They landed in the harbour of Waterford, where they had a settlement formerly; but though they obtained assistance here, they were defeated by the native Irish, both in Kerry and in Tipperary.  Sitric came with another fleet in 915, and settled at Cenn-Fuait.[204] Here he was attacked by the Irish army, but they were repulsed with great slaughter.  Two years after they received another disastrous defeat at Cill-Mosanhog, near Rathfarnham.  A large cromlech, still in that neighbourhood, probably marks the graves of the heroes slain in that engagement.  Twelve kings fell in this battle.  Their names are given in the Wars of the Gaedhil, and by other authorities, though in some places the number is increased.  Nial Glundubh was amongst the slain.  He is celebrated in pathetic verse by the bards.  Of the battle was said:—­