found a discussion by Seraffyn's nephew. It includes an mp3 of Seraffyn reciting the poem while his wife hums a tune in the background

http://www.brightcecilia.com/forum/showthread.php?t=3244

Hello,
I'm hoping someone will know a tune that my aunt used to sing. I've attached an .mp3 of it.

It's a home recording made by my dad in the 1950s, of a recitation of Yeats' "Song of Wandering Aengus" by my uncle, Donald Mork. He plays accompaniment on a lute, and Ania his wife sings a wordless minor key melody that I've never been able to identify. The recording isn't the best but it should suffice to convey the mood - "plaintive" I believe would describe it.

I'm no expert on Renaissance music, but I'm posting here on a hunch, and if I'm off the mark please let me know.

Thank you in advance for sharing your expertise.

Peter Mork

[One respondent suggests that the tune is based on Schubert's 'Standchen' and Mork replies:]

"Thanks for replying. The Schubert melody isn't the same, but there are points of similarity. Possibly is was inspired by a hearing of Schubert, or could it have been the other way around?

After I posted my question yesterday, I did some more research - one of those nights where you keep jumping out of bed to Google something you just thought of. Here's what I found.

My uncle later made a recording (under his minstrel name, Seraffyn) of 'Wandering Aengus' - same arrangement but with a different singer backing him up. In the album notes he says 'The accompaniment is an old lute exercise, to which a friend of mine composed the little melody you hear'. That friend turns out to be Bayard Rustin, known more as a civil rights activist but also a tenor who performed in the 30s in New York with Paul Robeson and Josh White (according to Wikipedia). The 'Wandering Aengus' melody was the tune to a song he wrote called 'I Saw Her As She Came and Went'.

Looking up Bayard Rustin on a folk music forum (mudcat.org) turned up the fact that Oscar Wilde's "Ballad of Reading Gaol" had been set to the same Rustin melody, and that a recording of "I Saw Her As She Came and Went", with Rustin's original words, was made in the the 90s by the folksinging trio of Gordon Bok, Ann Mayo Muir and Ed Trickett. I wasn't able to buy the whole song online, but the snatch provided by Amazon certainly sounded like the 'Wandering Aengus' tune.

The question then is, did Bayard Rustin actually compose this melody or did it come from somewhere else? I'm willing to field any theory but like hard facts the best!"