A topic in the Open Knowledge Graph — a free, open map of 15,290 topics and the order to learn them in.
Chromatic mediants are chords whose roots are a major or minor third away from the tonic, share at least one common tone with the tonic chord, but differ in mode or diatonic origin from the expected diatonic mediant. In C major, the chromatic mediants are bIII (Eb major), bVI (Ab major), III (E major), and VI (A major) — all third-related to the tonic but not all diatonic to C major. These chords move by chromatic or enharmonic half-step in one voice while sustaining the common tone, creating a smooth yet coloristically rich harmonic shift. Chromatic mediant relationships are a hallmark of Romantic-era harmonic language (Schubert, Liszt, late Beethoven) and are prevalent in film scores.
Play I–bVI–I and I–III–I progressions at the keyboard in several keys to internalize the coloristic 'slide' of chromatic mediants. Analyze film scores (John Williams, Howard Shore) and Romantic piano pieces for chromatic mediant progressions, comparing them to diatonic mediant chords (iii, vi) to hear the difference in color.
From your prerequisite work with borrowed chords, you understand how a composer can reach outside the diatonic scale and import chords from the parallel major or minor. Chromatic mediants are a specific, particularly beautiful application of that principle — chords whose roots sit a third away from the tonic, connected by smooth voice leading through a shared common tone. The defining feature is the combination of third relationship and chromatic contrast: the root is a third away, but the chord quality creates at least one note that is not diatonic to the home key.
In C major, the four chromatic mediants are bIII (Eb major), bVI (Ab major), III (E major), and VI (A major). Compare these to the diatonic third-related chords: iii (E minor) and vi (A minor). The chromatic versions differ in quality or in origin — E major and A major are borrowed from the parallel minor (or simply altered to major), while Eb major and Ab major are imported from C minor entirely. In each case, at least one pitch is foreign to the C major scale. Yet each chromatic mediant shares at least one note with the C major tonic triad (C–E–G): E major shares E, Ab major shares C, Eb major shares G, A major shares E. That shared common tone is the key to smooth voice leading — one voice holds the common tone while the other voices move by chromatic half-step, creating the characteristic "slide" of chromatic mediant harmony.
The perceptual effect is unlike any other harmonic movement. A perfect authentic cadence (V–I) creates resolution: tension followed by arrival. A secondary dominant creates a brief excursion to another key area. A chromatic mediant creates neither of these — instead, it creates a coloristic shift, like a sudden change in lighting or a modulation of emotional temperature without a change of location. The tonal center has not moved; the relationship to the tonic has not been reestablished through a dominant; yet something has clearly changed. This quality made chromatic mediants irresistible to Romantic composers who were exploring affect and color for their own sake, not just as functional steps in a harmonic progression.
The historical and practical context is directly connected: chromatic mediants are a signature sound of Schubert, Liszt, and late Beethoven, and they are now ubiquitous in film scoring because they produce exactly the emotional effect those composers prized — wonder, mystery, otherworldliness, sudden transport to a different emotional register. When you hear the theme of a fantasy film shift unexpectedly to a chord a third away, that is almost certainly a chromatic mediant. The voice leading that makes it smooth (common tone held, remaining voices moving by half-step) is not a coincidence — it is the structural reason the move works, and understanding it allows you to use chromatic mediants deliberately rather than stumbling upon them by chance.
Topics in reflective domains aren't scored by quiz answers. Read, reflect, and mark when you've thought it through.