. Before this, theorists viewed these as entirely different intervals above a bass note.
The (originally Traité de l'harmonie réduite à ses principes naturels ) is a monumental 1722 work by French composer and theorist Jean-Philippe Rameau . Often cited as the foundation of modern Western music theory, it shifted the focus of music from horizontal melody to vertical harmony , establishing the mathematical and functional rules for tonality. Core Theoretical Contributions Treatise on Harmony
: Provides rules for creating music, including how to handle chord progressions and modulation. Often cited as the foundation of modern Western
: Explores the physics of sound, focusing on string ratios, intervals, and the derivation of chords from a single "source" sound. : He was the first to formalize that
: He was the first to formalize that a chord like is the same entity as
The treatise is divided into four distinct books that move from abstract math to practical performance: