Music Theory
Acoustic Composition
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Where do Chords come from?

Why is 1722 so important?

1722 is the year that Jean-Philippe Rameau published his Traité de l’harmonie réduite à ses principes naturels (Treatise on Harmony reduced to its natural principles). This book outlined the concept of tonality based on major and minor scales and laid the foundation for most of the classical music that followed, and influencing the harmonic language of other tonal music like jazz and pop.

Rameau identified patterns in polyphonic music that lead to the classification of chords. We can define a chord simply as a group of 3 or more notes. The most basic type of chord, and the one most commonly used is the triad (3 note group). There are 4 types of triads:

The 4 triad types built on a C
  • Major Triad: M3 + m3
  • Minor Triad: m3 + M3
  • Augmented Triad: M3 + M3
  • Diminished Triad: m3 + m3

At the center of Rameau’s system is something all music students are familiar with on some level: the major scale.

The major scale is built on a pattern of seven melodic intervals: M2, M2, m2, M2, M2, M2, m2
Other ways to refer to this pattern are: W, W, H, W, W, W, H (W for whole step and H for half step)
and 2, 2, 1, 2, 2, 2, 1 (each number represents the number of half steps)

The harmonized major scale shows us all of the possible triads inside of any given key:

Notice the roman numerals to classify each triad’s position in the major scale. These numerals and chord qualities stay the same regardless of the major scale being used.

This alone was a great step forward for harmony, however, Rameau went one step further and described how each of these chords function and how they relate to each other.