"Remember the glories of Brian the brave... To light us to victory yet." Tell the invading Danes that we prefer "to bleed for an age ... than to sleep but a moment in chains." Do not let those that died "upon Ossory's plain" have fallen in vain
Brian Boru (Boruma), born c. 942, became king of Munster after the murder of his brother Mathgamain in 976, and then set out to become High King of Ireland. By about 1002, he was recognized as such by most major Irish lords.
Although Brian's enemies are called Danes in the song, in fact they were Viking raiders allied with rebels from Leinster (see, e.g. Mike Cronin, _A History of Ireland_, p. 8; Peter and Fiona Somerset Fry, _A History of Ireland_, p. 56). The two sides met at the Battle of Clontarf, on Good Friday 1014, and Brian's Munster forces were victorious though he was slain. In practice, that was a defeat for Brian, since it ended the fragile Irish unity. The Vikings did go away, for the most part -- but that was more because Swein Forkbeard and his son Canute were conquering England than anything else. - RBW, (BS)