I was thinking about Folk melodies that have been rewritten (& copyrighted) by writers in the field of Rock &/or contemporary popular music.From Elvis singing "Love Me Tender" (Aurie Lee"),Bob Dylan's "Blowin' In The Wind" ("No More Auction Block")& "Masters Of War"("Nottmun Town")John Lennon's "Happy Christmas (War Is Over) which,melodically is,to all intents, & purposes "Stewball"
A mention should also be made of George Harrison who wrote "Behind that Locked Door" a song whose meter & chord changes both owe a debt to "On Top of Old Smokie"
A (relatively) more recent example might be "Belfast Child" by Simple Minds which is yet another rewrite of "She Walks Through The Fair"
I was wondering how many other examples others might be able to think of?