What does polytonality refer to in music?

Polytonality is a compositional technique that involves the simultaneous use of two or more keys, creating complex harmonic and melodic textures. This technique allows composers to explore new soundscapes and tonal relationships that are not typically found in traditional tonal music. Polytonality can lead to rich dissonances and novel harmonic progression, providing a fresh musical language.

Such usage can be traced back to the works of composers in the early 20th century, such as Igor Stravinsky and Charles Ives, who experimented with multiple key centers in their compositions. By employing polytonality, composers can create a sense of conflict and resolution, allowing listener perception to shift between the different tonalities being presented.

Other concepts, such as the use of two or more tempos or the combination of different time signatures, pertain to rhythm rather than harmony, which are separate issues. Similarly, blending different musical genres doesn't specifically address the concept of multiple keys being used at once. Therefore, the correct understanding of polytonality is centered on the intersection of harmony and tonality, distinguishing it as a unique and innovative compositional strategy.