"Greensleeves is actually in the dorian mode, not a minor key. (No offense.)"

Well, it depends on which version. I've seen it written as strictly Dorian mode, and I've also seen it written as melodic minor. And I've seen mixed versions that start out Dorian and then go into melodic minor (most people tend to sing it that way). So which is the "authoritative" version? I prefer the Dorian, myself, but had I said "Dorian," I'm sure someone would have said, "No, it's in melodic minor."

Ya can't win.

Don Firth