MtheGM,

"by Pepys' time it had *probably* already been a popular favorite for many years." ~~ programme note by The King's Noyse.

*Probably* based on no evidence whatever to back it up. Pepys is the earliest reference. This falls into the category of those sloppy scholars who say something is vaguely "mediaeval" without any evidence whatever to back up the claim or date something further back than they wish it went.