I think musician should forget the theory and just play the notes. We get better music that way, as there's lots more time to practice.

"The earliest known copy of "The Campbells are coming" is that called "Hob or Nob" in Walsh's 'Caledonian Country Dances', IV, c 1744. (Out side of Scotland it retained this title, an is "Hob Nob" in 'Riley's Flute Melodies', New York, c 1817, with again the same key-mode) It has apparent keynote B with one sharp on the key signature, which would make it B phrygian, but it can also be coded as G major circular starting on the 1st of the scale. Those in Charles Gore's 'The Scottish Fiddle Music Index' are all coded G major, but there's no real way to decide one way or the other.

You will find the same two options for the Scottish "The White Cockade/The Ranting Highlandman" (1st tune in Aird's 'Airs', Jack Campin's website, which you can click on from mine). Here, however, the circular mode starts on the 3rd of the scale.

Circular tunes can be stinkers to figure out, because while the mode may seem a little bit odd, there is always one, and it does't seem all that odd. One case that shows very fast that this isn't the right way is when the last note is B and there are no sharps or flats on the key signature. You get a lot of locrians that way.

My favorite version of "Greensleeves" is not one of the 6 on my website, B168-73, that Simpson gave in 'The British Broadside Ballad and It Music'. I've given it now with an old song that I had forgotten to give previously. See "As I walked by myself" in Scarce Songs 2 for song and tune. www.erols.com/olsonw

"Greensleeves" is not a normal mode. It has an 8 note scale and there's no standard terminology for it. It's about as close as one can get to being half way between major and minor, or, another way of saying the same thing within narrower limits, is that it's half way between mixolydian and dorian. As for notation, it's simplest when you given it as dorian with a variable 7th. Those who want to believe that ancient Greeks had modes can if they like. Let's see them come up with real evidence. I spell the names in lower case, because as far as I'm concerned, they're just (faulty) names that have been generally accepted because of wide useage.