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Why Does the Key of C "Start" the Circle of Fifths and Not A?

Updated: Aug 13, 2023

In the world of music theory, intriguing questions often arise, ones that may seem simple but reveal profound insights into the historical and cultural context of musical development. One such question, deceptively simple yet brimming with complexity, asks why the musical "alphabet" begins with the note C instead of A. While A leads the English alphabet, in music, it's the key of C that holds the central position with no sharps or flats in its scale. What's the reasoning behind this musical enigma? Is it just a whimsical choice, or does it have deep-rooted connections to the historical evolution of music, theoretical foundations, and practical applications? This blog embarks on a journey through the Historical Roots, Theoretical Framework, and Practical Implications, unraveling the fascinating story behind why C takes the precedence over A in the musical universe.

1. The Historical Roots of the Enigma

a. The Ancient Greek Legacy

The origins of Western musical scales are rooted in Ancient Greece, with concepts like tetrachords and modes being central to their musical theory.

  • Tetrachords: A tetrachord is a series of four notes spanning a perfect fourth interval. Ancient Greeks used specific patterns within these tetrachords, primarily:

    • Diatonic: Whole-Whole-Half (e.g., E-F-G-A)

    • Chromatic: Half-Whole-Whole (e.g., E-F♯-G-A)

    • Enharmonic: Quarter-Quarter-Half (e.g., E-F-F♯-G♯)

By stacking two tetrachords and adding a whole tone in between, the Greeks constructed scales called modes.

  • Greek Modes: These modes were patterns of intervals that carried specific qualities. The most prominent modes included:

    • Ionian: First mode. This eventually became the major scale we recognize today (e.g., C-D-E-F-G-A-B-C)

    • Dorian: Second Mode. (e.g., D-E-F-G-A-B-C-D)

    • Phrygian: Third Mode. (e.g., E-F-G-A-B-C-D-E)

    • Lydian: Fourth Mode. (e.g., F-G-A-B-C-D-E-F)

    • Mixolydian: Fifth Mode. (e.g., G-A-B-C-D-E-F-G)

    • Aeolian: Sixth Mode. This served as a precursor to the natural minor scale and was characterized by a melancholic and introspective quality (e.g., A-B-C-D-E-F-G-A)

    • Locrian: Seventh Mode. (e.g., B-C-D-E-F-G-A-B)

These tetrachords and modes provided a robust framework for composing and understanding music in Ancient Greece, and they have influenced Western music theory ever since.

b. The Emergence of the Diatonic Scale

  • Diatonic Scale: Building on the modes, the diatonic scale with seven distinct notes became the foundation of Western music, known today as the major and minor scales.

c. The Adoption of the Natural Scale

The relationship between the notes C and A has a complex historical background:

  • Natural Scale: Historically, the natural minor scale (Aeolian mode) started on A, but the corresponding major scale was associated with C. These were seen as "natural" scales due to their lack of sharps or flats.

  • Transition from A to C: The shift from A to C as the central point of musical notation involves an intricate blend of Greek legacy, the Church's influence, and the evolution of musical instruments. It also reflects changes in tonal preferences and compositional practices across centuries.

d. The Church's Influence: Guido of Arezzo

The early Christian Church played a pivotal role in shaping Western music, particularly through the work of Guido of Arezzo:

  • Hexachord System: Guido of Arezzo, a medieval music theorist, introduced a hexachord system that used six-note patterns. He designated C (known as "Gamma Ut") as the principal starting note for the natural hexachord, a choice that began to establish C major as the "natural scale."

  • Guido's Influence: This system provided a way to notate music and teach singing, and it spread through the Church's extensive reach. Guido's choice of C had lasting implications, cementing the note's central position in music theory and practice.

2. The Theoretical Framework

a. The Structure of the C Major Scale

The C major scale plays a vital role in Western music theory and can be seen as a foundational block in understanding musical scales. It consists of seven distinct notes: C, D, E, F, G, A, B, followed by the octave C. This scale follows a specific pattern of whole and half steps, defined as:

  • Whole (W): Two half steps apart.

  • Half (H): One half step apart.

The pattern for the C major scale is: W, W, H, W, W, W, H.

This structure creates a sound that is often perceived as "happy" or "resolved." The absence of sharps and flats makes the C major scale an accessible entry point for beginners, especially on keyboard instruments, where all the notes fall on the white keys.

b. The Prevalence of Major Keys

Major keys have become the dominant tonality in Western music, symbolizing various positive or triumphant emotions. This prevalence can be linked to the harmonic and melodic principles that underpin much of Western music tradition. The natural hierarchy of chords in the major key has made it a go-to choice for composers and musicians.

Within the context of the C major scale, this meant that C major became the reference point for explaining and understanding major keys. The A minor scale, despite sharing the same key signature as C major (no sharps or flats), didn't achieve the same prominence. This is partly because the sound of the minor key is often associated with more somber or melancholic emotions.

Furthermore, the shift towards C major aligns with the tuning system called Equal Temperament. This system allowed for more flexibility in key changes and modulation, but it required a common reference point. C major, with its absence of sharps or flats, provided a straightforward and logical choice.

c. C Major and A Minor: A Shared Relationship

It's worth noting that C major and A minor share a specific relationship as relative keys. They both have the same key signature (no sharps or flats), but they start on different notes. C major begins on C, while A minor begins on A. The difference in starting notes creates different tonal characteristics. C major sounds bright and joyful, while A minor carries a more reflective or introspective quality.

This relationship illustrates the inherent complexity of music theory and demonstrates how changing just one parameter, such as the starting note, can lead to a profoundly different musical experience.

3. The Practical Implications

a. C Major and Keyboard Instruments

C major's distinctiveness and importance in Western music can largely be attributed to its visual simplicity on keyboard instruments like the piano and organ. This key uses only the white keys, creating a straightforward and intuitive layout for players. Unlike A major, which involves three sharps, C major doesn't require the same level of knowledge and dexterity to navigate. This accessibility has contributed to its perception as the "natural" or "default" scale, becoming a central point for learning and understanding music theory.

The structure of C major aligns effortlessly with the physical layout of the keyboard, allowing for a more natural hand position. Many beginner piano methods choose C major as the starting point due to this alignment. In contrast, A major's three sharps (F#, C#, and G#) would introduce an immediate complication for beginners.

b. Teaching Perspectives

The key of C major's simplicity and accessibility make it an ideal starting point for music learners, and this understanding has been embraced in educational contexts around the world. In piano lessons, in particular, the emphasis on C major is widely recognized as a pedagogically sound approach.

At Descant Music and Art Studio in Holyoke, MA, this principle is thoughtfully applied in their music education curriculum. The studio acknowledges the ease of C major in fostering early success and confidence. Especially in piano lessons, the studio's teachers choose to begin with the key of C major to instill foundational concepts and provide a gentle introduction to the keyboard's layout.

This approach creates a consistent and nurturing learning experience, bridging theoretical knowledge with hands-on practice. By grounding students in the C major scale, chords, and harmonic functions, Descant Music and Art Studio lays the groundwork for them to explore more complex scales and key signatures. The use of C major is not just a convenient choice but a considered decision that aligns with the studio's philosophy of making music learning an engaging and approachable journey for all.

c. Compositions in C Major

C major's natural sound and absence of sharps or flats have made it a favorite among composers across genres and periods. Its clean and uncluttered tonality has led to its use in a wide array of musical styles, from classical symphonies to modern pop songs.

In classical music, composers like Mozart and Beethoven have penned works in C major that are considered cornerstones of the repertoire. Mozart's Symphony No. 41, "Jupiter," showcases the grandeur and clarity possible within this key.

In the world of popular music, C major's accessibility has made it a go-to key for songwriters and producers. Countless pop and rock songs employ the key of C major, capitalizing on its bright, uplifting quality.


The reason why C major became the key with no sharps or flats is a complex issue rooted in historical, theoretical, and practical considerations.

Historically, the shift can be traced back to Guido of Arezzo's hexachord system in medieval music, where the "natural" hexachord was built on C, and C became the final or resting note in the Church's plainchant tradition. This made C a critical note in the early Christian Church music system.

In terms of theoretical frameworks, the music theory developed during the Renaissance and Baroque periods began to favor the Ionian mode (which starts on C) as the basis for the major scale. This change might have been driven by the Ionian mode's musical properties, which suited the harmonic and melodic conventions of the time. This led to the adoption of C major as the "natural" major key.

From a practical standpoint, the development and tuning of keyboard instruments like the organ and harpsichord may have contributed to this shift. C major's pattern of white and black keys made it a convenient starting point for learning and teaching.

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