Helen wrote: I just found this video commentary on Sumer is Icumen In, by James Hargreaves:

We already had arguments about that video. See https://mudcat.org/thread.cfm?threadid=159390&messages=27 (the dozen or so postings near the end of the thread).

I should perhaps add that, like Child and Bronson and Kittredge and many older ballad scholars, but unlike most folklorists of today, I have given a lot of attention fo the subject of Middle English folk song. There are 91 songs in the Traditional Ballad Index which I cite with the keyword "middleenglish," all of which have at least some notes explaining their sources and why I (or someone, often Richard Leighton Greene) thought them traditional.