Alice I found something interesting on this song, although not the songs author. There is an Irish laguage song with the the title, AN TRÉIGEAN(THE DESERTION). the author is credited to a Tom Sailí Ó Flaithearta. I don't have any idea how old the song is. Never to contradict myself, I did find one reference to this name as actor in a play here: Cré na Cille. there is is one verse I found particularly interesting:

Shuigh mé síos liom féin ar an Tulláinín úd féir,
San áit ar chéadléirigh tú do ghrá dom
Dúirt an ghealach liom is na réalta, is an ghaoth i mbarr na gcraobh
Gur éalaigh tú thar sáile uaim le náire

This roughly translates to:

I sat myself down alone on yonder grassy land,
The spot where you first proclaimed your love to me
The moon and the stars told me as the wind in the top of the branches
That you slipped away across the ocean with shame.

In the English version, the author rhymed alone and stone in the same way the Irish Language version rhymed féin and féir.

This indicates to me that the author of the English Language song was aware of not only the melody, but the Irish Language song and had some Irish as well.

Brían