A Neat, Useful Set Of Changes

Those are also almost the chords to Dylan's "Don't Think Twice, It's All Right."

As someone who has reasonable familiarity with British Isles folk music, I'm aware of dozens of older folk tunes that have been taken pretty wholesale and set to new lyrics. "A Drop of Nelson's Blood" is the same tune as "The Drunken Sailor"; Patrick Kavanaugh set his poem "Raglan Road" (1946) to the tune of "The Dawning of the Day" (Edward Walsh, 1847). "Wild Mountain Thyme" (also known as "Purple Heather" and "Will Ye Go, Lassie, Go?") is a Scottish/Irish folk song. The lyrics and melody are a variant of the song "The Braes of Balquhither" by Scottish poet Robert Tannahill (1774–1810) and Scottish composer Robert Archibald Smith (1780–1829), but were adapted by Belfast musician Francis McPeake into "Wild Mountain Thyme" and first recorded by his family in the 1950s. And so on and so on.

Sometimes the words stay the same but the melody and chords change: I've heard at least three different melodies and chord changes for the 17th century Irish traditional song "Mháire Bhruinneal".

And this behavior's not limited to the British Isles. The American folk song "Streets of Laredo" (1924 by Frank Maynard) is just new lyrics set to an Irish song from the late 1600s/early 1700s titled "The Bard of Armagh." For that matter, the theme song for the 60s TV show "Gilligan's Island" is credited as having both music and words written by Sherwood Schwartz and George Wyle -- but I can tell you for certain that while they may have written the lyrics, the melody and chords were heavily 'borrowed' from "Step It Out, Mary" by the Irish musician Sean McCarthy, written a good decade earlier in 1955. I occasionally play "Step It Out, Mary" on solo gigs and end the song by singing the first verse of the Gilligan Island theme.

I should point out that generally "Trad" musicians aren't bothered by the borrowing of melodies and chord changes and happily engage in it themselves. For that matter, I almost always play "Saint James Infirmary" on solo gigs, and there are several variant lyrics and melodic/chord changes to that tune — so there's no 'canonical' version of that song. Every musician who plays it is essentially creating their own version.

Bob changed the chords to some of his songs over the years.  I learned Girl From The North Country from his Freewheelin' LP and the chords I used were:

[C]If you're [Am] travelin' in the [F] north country [C] fair
Where the winds hit [Am] heavy on the [F] border [C] line
Remember [Am] me to [F] one who lives [C] there
She once [Am] was a [F] true love of [C] mine

Although I think Bob played it in B or Bb, the chords were relatively the same.
Years later he re-recorded it as a duet with Johnny Cash and they used:

[C]If you're (Em) travelin' in the [F] north country [C] fair
Where the winds hit (Em)  heavy on the [F] border [C] line
Remember (Em)  me to [F] one who lives [C] there
She once (Em) was a [F] true love of [C] mine

Once again, I believe they were in G or A, but the chords were relatively the same.

I first learned House Of The Rising Sun from a Josh White LP and later a Joan Baez LP.
These are the chords that Dave Van Ronk made up for House Of The Rising Sun, also used by Bob Dylan and The Animals.  The tune changes at the end of each line.  I find it interesting that Eric Burdon sang, "...many a poor boy".  I realise that there are male prostitutes, but it sounds odd to me.

There (Am) is a (C) house in (D) New Or(F)leans
They (Am) call the (C) Rising (E) Sun (E7)
And it's (Am) been the (C) ruin of (D) many a poor (F) girl
And (Am) me, oh (E) God, I'm (Am) one. (E7)

These are the chords used by Josh White, Joan Baez, Woody Guthrie, Ramblin' Jack...

There (Am) is a (C) house in (E) New Or(Am)leans
They call the (C) Rising (E) Sun (E7)
And it's (Am) been the (C) ruin of (E) many a poor (Am) girl
And me, oh (E) God, I'm (Am) one. (E7)

That being said, I can't get Don't Think Twice to fit the chords for They're Red Hot. . .

when I type that by its self ist say You must provide a Message
it also makes everything italic


(em)(/em) using square bracket sets paragraph italic