Hrothgar: “It has also been used for an Irish song called (let's not argue too much about Gaelic spelling - just accept that the spelling is as confusing as the pronunciation) "Gro ma chridhe."

If I remember correctly, it starts "Last night I had a happy dream."

Bob the Postman: “Meanwhile, a hint from the main Mudcat "Strangest Dream" thread leads to this Irish song about a Happy Dream, which seems to bring us closer to 1930s France than the Little Country Trio connection.”

Gra-mo-chroi. I'd Like to See Old Ireland Free Once More
“DESCRIPTION: "Last night I had a happy dream* ... I thought again brave Irishmen Had set old Ireland free." Some modern heroes are named and Father Murphy and the Wexford men of ninety-eight. "It's Gra-mo-chroi, I'd like to see old Ireland free once more"
AUTHOR: unknown
EARLIEST DATE: 1912 (Olochlainn-IrishStreetBallads)”

*These seem to be the 1960s lyrics in all my stuff. When did the happy/pleasant dream lyric actually-really-truly first appear?

Sort of the same melody but way up-tempo:
Oh! Grammachree, I'd like to see old Ireland free once more,
And see the times we used to have in the good old days of yore;
I'd like to see the harp and shamrock waving over Erin's shore,
I'd like to see old Ireland free, oh, grammachree asthore!
[Land League Band, John W. Kelly, c.1907?]