ABSTRACT
The progressive weakening (and eventual breakdown) of the tonal system in the late-nineteenth century, however, led some early twentieth-century composers to look for alternative methods of pitch organization. Many post-tonal works that do not feature any kind of traditional tonality are nevertheless based on some principles of pitch centricity, the organization of pitches around one or more pitch centers, although not necessarily including a system of pitch hierarchies around a tonic. The twentieth century may thus be one of the most complex, rich, and fragmented periods in music history (similar in many ways, from this point of view, to the Renaissance, a period the readers can also think of as a mosaic of independent but interchangeable and intersecting styles). The “common-practice period” was replaced, in the twentieth century, by a “diverse-practices period.”.
