Brian Boru in the Irish (Brian Bóramha i nGaeilge)

ALAN STIVELL in BRIAN BORU 

Brian Boru united Ireland. Quite a rare feat! Around a thousand years ago. 

This music is from Alan Stivel, who is a Breton from France.

Ancient Irish flag.

Alan Stivell - Brian Boru 

http://www.youtube.com/watch?v=atxyOCHFd8U

Here is the translation, which is from the Irish as well as Breton.

http://lyricstranslate.com/en/brian-boru-brian-boru.html

This information about the six Celtic nations is from Wikipedia http://en.wikipedia.org/wiki/Celtic_nations:

The six territories recognized as Celtic nations are Brittany (Breizh), Cornwall (Kernow), Ireland (Éire), the Isle of Man (Mannin), Scotland (Alba), and Wales (Cymru).^[1][2] Each of these regions has a Celtic language that is either still spoken or was spoken into modern times.^[3] In addition, areas of north-western Spain and Portugal, particularly Galicia, Cantabria and Asturias and Minho, Douro, Tras-os-Montes (Northern Portugal) are oftentimes identified as Celtic, due to the unique culture of the region. Unlike the others, however, no Celtic language has been spoken there in modern times.^[4][5][6] Before the expansions of the Roman Republic and Germanic tribes, a significant part of Europe was Celtic.^[7]