It is based on a tune by the incredibly prolific poet and composer 'Anonymous' that is sung at the beginning and end of the Fantasia.
Unlike the other two movements of the "Symphonies on Ancient Tunes", this is from the Renaissance (Tudor) period. The text, with a gender change, was used in Shakespeare's "Othello". It is sung by Desdemona before she is murdered by Othello.
This is performable without the vocal at the beginning and end but after I put it in my original MIDI file, those who heard it felt it should be left in. Originally a Virtual Singer voice, the countertenor here (a considerable improvement) is David W. Solomons:
David Solomons Music Site
The poor soul sat sighing
by a sycamore tree,
Sing O the green willow.
With his hand in his bosom
and his head upon his knee,
Oh willow, willow, willow, willow.
Oh willow, willow, willow, willow
My garland shall be.
Sing O the green willow.
Willow, willow, willow
I mean the green willow
My garland shall be.
He sighed to his singing
and made a great moan,
Sing O the green willow.
I am dead to all pleasure,
my true love is gone.
Oh willow, willow, willow, willow (etc.)
Take this for my farewell
and latest adieu,
Sing O the green willow.
Write this on my tomb,
that in love I was true.
Oh willow, willow, willow, willow (etc.)
(This last stanza is not used in this setting.)