During which decade was 12-tone music predominantly developed?

12-tone music, also known as dodecaphony, was predominantly developed in the 1920s, primarily through the work of Austrian composer Arnold Schoenberg. This compositional technique involves using all twelve tones of the chromatic scale in a particular order or series, allowing for a structured approach to atonality. Schoenberg's innovations during this decade laid the groundwork for subsequent developments in modern music, influencing numerous composers who followed.

The 1930s saw the continuation and adaptation of some of these ideas, while the 1950s marked a time of further exploration in serialism by composers like Pierre Boulez and Milton Babbitt. The 1980s, on the other hand, focused more on postmodern styles and varied musical languages rather than the foundational development of the 12-tone technique. Therefore, the 1920s is the decade most closely associated with the establishment and practice of 12-tone music.