This force Brian gathered all his energies to oppose.  With his own Munster clansmen, aided by all the fighting men of Meath and Connaught, with his five sons and with his old rival, King Malachy of Meath, fighting under his banner, he marched down to the strand of Clontarf, which stretches from the north of Dublin to the out-jutting promontory of Howth, and there, upon Good Friday, 1014, he encountered his Leinster rebels and the Viking host of invaders, ten thousand strong it is said, and a great battle was fought, a battle which, beginning before the dawn, lasted till the sun was beginning to sink.

To understand the real importance of this battle, we must first fully realize to ourselves what a very old quarrel this was.  For three long weary centuries Ireland had been lying bound and broken under the heel of her pagan oppressors, and only with great difficulty and partially had escaped within the last fifteen or sixteen years.  Every wrong, outrage, and ignominy that could be inflicted by one people upon another had been inflicted and would most assuredly be inflicted again were this battle, now about to be fought, lost.

Nor upon the other side were the motives much less strong.  The Danes of Dublin under Sitric stood fiercely at bay.  Although their town was still their own, all the rest of the island had escaped from the grasp of their race.  Whatever Christianity they may occasionally have assumed was all thrown to the winds upon this great occasion.  The far-famed pagan battle flag, the Raven Standard, was unfurled, and floated freely over the host.  The War-arrow had been industriously sent round to all the neighbouring shores, peopled largely at that time with men of Norse blood.  As the fleet swept south it had gathered in contingents from every island along the Scotch coast, upon which Viking settlements had been established.  Manx men, too, and men from the Scandinavian settlements of Angelsea, Danes under Carle Canuteson, representatives, in fact, of all the old fighting pagan blood were there, and all gathered together to a battle at once of races and of creeds.

On the Irish side the command had been given by Brian to Morrogh, his eldest son, who fifteen years before had aided his father in gaining a great victory over these same Dublin Danes at a place called Glenmama, not far from Dunlaven.  The old king himself abstained from taking any part in the battle.  Perhaps because he wished his son—­who already had been appointed his successor—­to have all the glory and so to fix himself yet more deeply in the hearts of his future subjects; perhaps because he felt that his strength might not have carried him through the day; perhaps—­the annalists say this is the reason—­because the day being Good Friday he preferred praying for his cause rather than fighting for it.  Whatever the reason it is certain that he remained in his tent, which was pitched on this occasion not far from the edge of the great woods which then covered all the rising ground to the north-west of Dublin, beginning at the bank of the river Liffy.