What is "greensleeves"

"Greensleeves" is a traditional English folk song and tune, over a ground either of the form called a romanesca; of its slight variant, the passamezzo antico; of the passamezzo antico in its verses and the romanesca in its reprise; or of the Andalusian progression in its verses and the romanesca or passamezzo antico in its reprise. The romanesca originated in Spain and is composed of a sequence of four chords with a simple, repeating bass, which provide the groundwork for variations and improvisation.

A broadside ballad by this name was registered at the London Stationer's Company in September 1580, by Richard Jones, as "A Newe Northen Dittye of ye Ladye Greene Sleves". Six more ballads followed in less than a year, one on the same day, 3 September 1580 ("Ye Ladie Greene Sleeves answere to Donkyn hir frende" by Edward White), then on 15 and 18 September (by Henry Carr and again by White), 14 December (Richard Jones again), 13 February 1581 (Wiliam Elderton), and August 1581 (White's third contribution, "Greene Sleeves is worne awaie, Yellow Sleeves Comme to decaie, Blacke Sleeves I holde in despite, But White Sleeves is my delighte"). It then appears in the surviving A Handful of Pleasant Delights (1584) as A New Courtly Sonnet of the Lady Green Sleeves. To the new tune of Green Sleeves.

The tune is found in several late-16th-century and early-17th-century sources, such as Ballet's MS Lute Book and Het Luitboek van Thysius, as well as various manuscripts preserved in the Seeley Historical Library at the University of Cambridge.