Just a hunch open mike perhaps you are thinking of the song Aisling Gheal

In his notes on Aisling Gheal, Brian O'Rourke points out:

For most people who have been through the Irish educational system, the word 'aisling' will connote a poem or song in which the poet sees — or dreams that he sees — a beautiful woman who turns out to be Ireland lamenting her woes.

See the link below for the article.

http://www.standingstones.com/aisling.html

Or Roisin Dubh ("Dark Rosaleen"),

In the figure of Roisin Dubh ("Dark Rosaleen"), a Gaelic poem translated by James Clarence Mangan in 1835, the name became a poetic symbol of Ireland, reflecting the Irish tradition of disguising outlawed patriotic verse as love songs where she is told not to be downhearted for her friends are returning from abroad to come to her aid.

Just a thought. Dont know if either of these answer your question.
fliss