Source: P.W. Joyce, Old Irish Folk Music and Songs.¹

“I copied […] about 1873 from a MS. lent me from near Lough Conn, County Mayo.”

Of possible relevance here is the note regarding the source for the song ‘Owen Core’:

“About twenty years ago a young national teacher from Mayo lent me a music book containing a great number of beautiful Irish airs, extremely well written, and nearly all belonging to Connaught, which had been copied in a district on the shore of Lough Conn. Among these airs I found the present one, and copied it with many others.”²

1. P.W. Joyce (ed.), Old Irish Folk Music and Songs, A Collection of 842 Irish Airs and Songs Hitherto Unpublished. Longmans, Green, And Co., London, New York, Bombay, And Calcutta. Dublin: Hodges, Figgis, & Co., Ltd. 1909, p143.
2. P. W. Joyce (ed.), Irish Music and Song: A Collection Of Songs In The Irish Language Set to Music. M.H. Gill and Son, Dublin, 1901, p4.