Why is it that notes "start" with C? In key signatures, for example, C Major is the basis and accidentals are added for all other key signatures. I know that the musical alphabet starts with A and goes to G, so why is C the base note of standard notation and keys? Why isn't A the basis?

  • Because Do is the first note, following by Re, Mi, Fa, Sol, La, Si, and Do is C – phuclv Sep 18 '14 at 8:06
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    Cart before the horse, Lu. Do is C because C is the base note. – corsiKa Nov 24 '15 at 3:58
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    In a parallel quirk of history, the first drive on a Windows computer is usually C: rather than A:. A different reason of course but in both cases, it is too hard to change now and we live with the situation. – badjohn Jul 12 '17 at 4:39
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    The first floppy drive was A:. When there was only one, it could be remapped as B: for disk copying. When hard drives appeared the first one was C:. – Laurence Payne Aug 30 '17 at 22:50
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    Though some ingenious justifications have been suggested, I don't think we're going to get a better answer than 'because it is'. – Laurence Payne Aug 30 '17 at 22:52

This was already partially answered here, and there's a pretty comprehensive explanation here.

Notes do not "start" with C; C major is just the easiest major key to notate in modern notation. The concept of a major key came about long after letters were assigned to the notes. Before there were major (and minor) keys, people used modes, usually just using the notes of the modern white keys and starting and ending in different places. The Ionian mode (which became modern major) was a late addition to the modes.

So it's historical accident that C major is treated as "basic."

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    In other words, it's not that "C" was given any prominence (directly) as the "base note" but rather the Ionian became the "base mode". The latter names themselves favour the Aeolian as the "base mode". – James Tauber May 20 '11 at 4:18
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    possibly relevant video youtu.be/NRDwrKMan_Q – Dave Oct 7 '15 at 17:38
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    @JamesTauber but the Aeolian mode was also invented at the same time as the Ionian, in the middle of the 16th century, and has nothing to do with the assignment of letter names to the notes, which had happened over 5 centuries earlier. – phoog Mar 29 '19 at 16:36

I feel this question deserves a shorter, more to the point answer:

Because when they decided to name the notes with letters, they took a minor scale and named the notes "naturally": A, B, C, D, E, F, G. This is what we know as the A minor scale.


Therefore the choice of names was accidental - it just happened that they considered a minor scale instead of a major one. Now if we want to use the same "natural" notes in a major scale, then we need to start with C.

If, however, we were to turn back time and influence the early notation to use a major scale as a basis, then they would name "A" the first note in the natural major scale, and then today we would talk about A major as the "standard" scale. But of course this "alternate" A would be the same frequency as "our reality" C.

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    The letter names have existed at least since Guido d'Arezzo, which was centuries before there was such a thing as a natural minor scale. Even then, by Guido's time, there was one note before A, called Γ (Greek gamma). That seems to imply that in some earlier system, A was the first note for some reason, but it's not clear to me when, why, or how. In Guido's system of hexachords, A was one of four notes that could be in any of the three hexachords; it could be la of the natural hexachord (c to a), mi of the soft hexachord (f to d), or re of the hard hexachord (g to e). – phoog Mar 29 '19 at 16:30
  • I think the issue with this answer is that a) people obviously seem to disagree that the minor scale was even invented when the notes were named, and b) it doesn't explain who "they" is, so it's still fairly unsatisfying. Though it would probably make a sufficient explanation to a layman or beginner. – awe lotta Dec 30 '19 at 3:38

"... the choice of names was accidental - it just happened that they considered a minor scale instead of a major one. Now if we want to use the same "natural" notes in a major scale, then we need to start with C."

I don't think it was accidental that first mode is A minor. Rather, it represents the music of the people that created music notation: Monks. An 'Aeolian-like' sound was the their preferred mode of music making. The notes of that "Aeoloian-like" sound would have been a minor scale. That is the sound they liked to sing- and the first note of it they named 'A'. Over the course of time there was a shift brought about by the development of the tempered scale, as well the development of craftsmen skilled in tuning instruments, which made it possible for Bach to write his music (dig The Well Tempered Clavier). Bach is really the beginning of modern music and, in a way, modern consciousness. When we ponder the key of C on the piano and wonder why it's not called A, it's because we don't perceive the bias we have for the major scale. It's become part of the foundation of Western consciousness. In my humble opinion...

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    This is what I learned in a music theory course. Unfortunately, I did not ask the prof if we have any examples of medieval plain chants that use Aeolian, because it seems rather difficult to find them. See here for starters: Gregorian mode - there doesn't seem to be any particular focus on Aeolian mode at all. – Stinkfoot Aug 31 '17 at 0:15
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    Yes that's why I wrote "Aeolian-like" . They had many modes available, and looking at the Wikipedia page you have linked there is shown 8 tonalities, and #2 shows "Hypodorian" which is notated as a natural A minor scale... which we call Aeolian mode. They had lots of choices. It could be that they omitted tones or shifted modes as needed in performance. – David Silberberg Sep 2 '17 at 18:41
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    Understood. But that takes the edge off of this answer. – Stinkfoot Sep 2 '17 at 19:18
  • @Stinkfoot the aeolian mode was invented in 1547, well after the end of the middle ages. The letter names were established over 500 years earlier. – phoog Mar 29 '19 at 16:33

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