LIghter's link didn't work for me.

Try https://mudcat.org/thread.cfm?threadid=22761#1386063

If that doesn't work, find George Seto's 2005 post at https://mudcat.org/thread.cfm?threadid=22761 or click on the link to "(origins) Origins: History of the Song Danny Boy (48)" at the top of this page.

re Lighter's summary, Bunting published an air similar to the Londonderry Air, but the air as transcribed by Jane Ross was published in George Petrie's 1855 collection (the book was first published in parts, commencing in 1853). I'd say it is Petrie's collection that Lighter referred to when he wrote "Bunting".

Audrey writes that "It wasn't called the Londonderry Air in print until 1894 when this was the name given it as the tune accompanying Irish Love Song, written by Katherine Hinkson, in a book edited by Alfred Perceval Graves called Irish Song Book. Graves and Hinkson wrote three sets of words to the air between the late 1870s and 1894 but it became a popular success only after Fred Weatherly wedded his verses of Danny Boy to it in 1912 and published it in 1913"

The 1918 Londonderry Sentinel article I submitted here does suggest that people in counties Derry and Donegal had some familiarity with the tune (or something similar) before it became famous. Thank you, Lighter, for filling in information (from Wikipedia) of the song which informed Dr. Annie Patterson's memories reported in 1918. I did not know of Dr Patterson, but she has a Wikipedia entry: https://en.wikipedia.org/wiki/Annie_Patterson. She adjudicated at the first Feis Doire Colmcille in Derry in 1922 as civil war loomed in Ireland. https://www.derryjournal.com/news/people/feis-doire-colmcille-a-century-of-culture-from-a-city-of-music-song-and-dance-3555017

Audrey also quotes from Coleman's article in Musical Times which was the basis for the Londonderry Sentinel article