I am not an expert at this by far, so please correct me where I'm wrong, but...
Doesn't much of this depend upon which charts are used? By that I mean, because scales and tunings *have* changed over the centuries, hasn't much of the old, old music been re-written to conform to the modern scales? For example, something like today's "Greensleeves" actually bears only a superficial melodic resemblence to the traditional versions of it because it was original written in scales not accessable by today's fretted instruments - let alone translateabel to today's scales.
Now perhaps for some of the more recent classical guys for whom we still have the original charts this may not be so much the case, maybe. But go far enough back, where there were only "traditional" arrangements (often more than one) passed down pretty much untranscribed, changes/adaptations have been made to the actual compositions in order to fit modern scales and instruments.
Is that understanding waaaay off?
G.
Not quite. The "traditional" western scales date back to Pythagoras, although the 12-note (as opposed to 12 tone) scales became more prevalent during the middle ages, used in Gregorian Chants, as well as by the minstrels. However, there are several things you have to keep in mind about music of that era dealing with tuning and tonality (although, come to think of it, modern rock and a lot of electronic dance music isn't that far off in that regard... but I digress...)
1. Equal temperament was not used until early 1800s.
2. Most brass winds could not play chromatically (the exception being the Trombone and its predecessor Sackbut), which necessitated the use of instruments of different tunnings (Trumpets in D, F, Bb, E, C and A being specially popular... same with Horns).
3. Modulation and chromaticism were almost unheard of, at least beyond the Tonic, Supertonic and the Dominant (I - IV - V). Kind of like today's pop
Jazz is different story
So, given that, older tunings tended to favor certain tonalities (ones with few flats or sharps, such as F major, or D minor or E dorian), at the expense of others. This also included the tuning of keyboard instruments such as the harpsichord and the organ. Several variations on Pythagorean and "Just intonation" tunings were used, which made the tonality that they were centered around sound a lot more resonant (compared to our equal temperament) when playing chords as the notes in the chords reinforced each other's natural harmonics... which is what the old brass instruments were limited to anyway...
So, the end result was their stuff sounded more harmonious and resonant, at the expense of tonal (in the sense of a scale not sound quality) flexibility.
However, the differences among the different tunnings note for note are several cents, usually not more than 10-15 cents in the most far-off situations, compared to Equal Temperament.
Sooo... after all this long-winded stuff, what I am getting at is that the scales themselves haven't really changed much, except that nowdays we tend to not use modal scales as much as they did in the past (Jazz notwithstanding), only the way we tune our instruments. And although this does affect the overall sound, it doesn't fundamentally alter the melodic aspect of the composition.
Overall, what your tuning reference is (A=440Hz or something else) is going to affect the range far more than the actual tuning methodology. In fact, even nowdays, many a capella groups will tend towards the natural "temperaments", as they sound more harmonious, a prime example being barbershop quartets.
Well, there Glen, I think I am going to get a certain someone come after me for long posts now
Hope this long winded nonsense actually makes some sense and answers your question.