Diabolus in Musica

Diabolus in Musica, Latin for "the devil in music," refers to a dissonant interval historically considered unsettling or unstable—specifically the tritone, spanning three whole tones. During the Middle Ages and Renaissance, it was often avoided in composition due to its perceived dissonant qualities, thought to evoke tension or evil. Over time, musical understanding evolved, and the tritone became an essential element in harmony and jazz, valued for its ability to create suspense and color. Today, it is recognized as a key interval with rich expressive potential, illustrating how musical perceptions can shift over centuries.