Why was the tritone called the Devil's Interval?

The 'Devil's Interval' that was banned by the medieval church.

Diabolus in Musica

The tritone—an interval spanning three whole tones—has a uniquely unsettling sound. Medieval musicians called it "Diabolus in Musica" (the Devil in Music).

What Makes It Special?

The tritone divides the octave exactly in half, creating:

  • Maximum acoustic tension
  • Ambiguous tonal center
  • Strong pull toward resolution
  • Dissonance that demands movement

The Church Ban (Myth vs. Reality)

Popular legend says the Church banned the tritone. In reality:

  • It was avoided in sacred music, not legally banned
  • The prohibition was aesthetic, not theological
  • Composers used it carefully for tension

Modern Usage

The tritone now appears everywhere:

  • Jazz: Foundation of dominant seventh chords
  • Blues: Essential to the blues sound
  • Metal: Creates heaviness and tension
  • Film scores: Signals danger or evil

Famous Tritone Examples

  • "Black Sabbath" opening riff
  • The Simpsons theme
  • "Maria" from West Side Story
  • Jimi Hendrix's "Purple Haze"