The set recorded on Aislingí Ceoil (see above) is the same as the first three verses Brian quotes, and is from the same original source. "Mary" in verse two, however, is given as "maidhre".
The song was noted from Peig Ní Dhonnchadha (Peg O'Donoghue) by A. Martin Freeman in 1914. It was (first?) published in The Journal of the Folk-Song Society, vol VI (issue 24) 1921, 224-226. Freeman printed 5 verses (those above, plus another in penultimate place), using an early (and now obsolete) form of Reformed Irish Spelling for the transcriptions.
I quote here the translation into English (first three verses above) provided with Aislingí Ceoil. It was made by Liam Mac Con Iomaire, and seems to fit the tune quite elegantly.
A Vision Bright
A vision bright beguiled in sleep me As I lay feebly bereft of cheer; In a river valley I wandered gaily In conversation with my true love dear. The host of foreigners and host of Gaeldom In battle baring their sword and spear; And the word went out in loud lamentation That the day of saints was now drawing near.
Then soon I gazed on a fair young maiden With shining hair falling to the ground; Her flowing tresses like stars cascading, Falling in waves to her ankles down; Sweeping the dew off the meadow early And tripping gaily with footsteps light; Her two round breasts on her bosom neatly, Her cheeks were berries and her throat was white.
And when I greeted my love in Gaelic, In manner gracious she did reply; "O, flower of men, please do not take me, I am underage and a maid forby. If our lovemaking conceived a baby And if your blame then you should deny, I would leave Erin and death would face me And my ghost would plague you all through your life".