Why does Bruce O. bother ? Nobody listens....

The earliest known version of the melody dates from 1580 or so. It it the version now used for "What Child is this ?" The attribution to Henry VIII is probably about as reliable as an attribution to Old King Cole would be. But I have encounterd even more outrageous claims for other tunes.

A variant in 6/8 time, documented later, was used in the 17th and 18th centuries. It is sometimes called "Green Sleeves and Yellow Lace" and "Green Sleeves and Pudding Pies".

A Kidson/Neal book of 1916 prints a third variant, in 2/4 time.