<P> 20th Century music brought a new freedom and wide experimentation with new musical styles and forms that challenged the accepted rules of music of earlier periods . The invention of musical amplification and electronic instruments, especially the synthesizer, in the mid-20th century revolutionized popular music and accelerated the development of new forms of music . </P> <P> As for classical music, two fundamental schools determined the course of the century: that of Arnold Schoenberg and that of Igor Stravinsky . </P> <P> Classical music is a broad, imprecise category, including music produced in, or rooted in the traditions of art, ecclesiastical and concert music . A music is classical if it includes some of the following features: a learned tradition, support from the church or government, or greater cultural capital . Classical music is also described as complex, lasting, transcendent, and abstract . In many cultures a classical tradition coexisted with traditional or popular music, occasionally for thousands of years, and with different levels of mutual borrowing with the parallel tradition . </P> <P> Sub-Saharan African music is by a strong rhythmic interest that exhibits common characteristics in all regions of this vast territory, so that Arthur Morris Jones (1889--1980) has described the many local approaches as constituting one main system . C.K. also affirms the profound homogeneity of approach . West African rhythmic techniques carried over the Atlantic were fundamental ingredients in various musical styles of the Americas: samba, forró, maracatu and coco in Brazil, Afro - Cuban music and Afro - American musical genres such as blues, jazz, rhythm & blues, funk, soul, reggae, hip hop and rock and roll were thereby of immense importance in 20th - century popular music . </P>

Where did the idea of music come from