African-American music is an umbrella term covering a diverse range of musics and musical genres largely developed by African-Americans. Ragtime, Jazz, blues, house, Doo Wop, rhythm and blues, rock and roll, hip hop, Disco and techno constitute the principal modern genres of African-American music. Their origins are in musical forms that arose out of the historical condition of slavery that characterized the lives of black Americans prior to the American Civil War. The modern genres were developed during the late 19th century by fusing European musical styles (characterized by diatonic harmony within the framework of equal temperament) with those of African origin which employed the natural harmonic series. The exceptions are hip hop, house and techno, which were formed in the late 20th century from earlier forms of African-American music such as funk and soul.Following the Civil War, black Americans, through employment as musicians playing European music in military bands, developed new musical styles such as ragtime and what would become known as jazz. In developing this latter musical form, African Americans contributed knowledge of the sophisticated polyrhythmic structure of the dance and folk music of peoples across western and sub-Saharan Africa. Together, these musical forms had a wide-ranging and profound influence over the development of music within the United States and around the world during the 20th century.The earliest jazz and blues recordings were made in the 1920s. Later periods saw considerable innovation and change. African-American genres have been highly influential across socio-economic and racial groupings internationally, and have enjoyed popularity on a global level.