The association of Alwyn with this song is a common phenomenon on the web... the evolution of threaded discussion into substantiated fact. We witnessed the same thing happen to another popular song... Pete St. John's Fields of Athenry, whose lyrics for a time were erroneously tagged to a non-existent traditional tune.
By having sequenced a midi of The Isle of Innisfree I am embarrassed to have been partly responsible for this musical fiction, as my midi spread across the web as some kind of authenticated proof of the traditional tune.
I myself have experienced the wonder of such web metamorphosis. My one and only lyrical creation, An Emigrant's Daughter, became 'Irish traditional' within two years of its creation in 1998!
On the plus side of this experience...
...we now have a complete appreciation of the background of the The Isle of Innisfree and of its author
...we have welcomed a new 'Catter in the form of Gerard
...hundreds of us are singing the tune anew
...the record sales for both Gerard and Carmel Quinn will hopefully increase as a result of our thread!
Now, to reprove my metamorphosis theory I will make mention of the 'fact' that White Christmas is based on an old Gaelic air titled Herding My Goats. Set your stopwatch! ;-)