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:
At the center of Rameau’s system is something all music students are familiar with on some level: the major scale.
The harmonized major scale shows us all of the possible triads inside of any given key:
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.