The first appearance of the blues is often dated to after the ending of slavery and, later, the development of juke joints. It is associated with the newly acquired freedom of the former slaves.
Blues is a music genre and musical form which incorporated spirituals, work songs, field hollers, shouts, chants, and rhymed simple narrative ballads. The blues form, ubiquitous in jazz, rhythm and blues and rock and roll, is characterized by the call-and-response pattern.
The call-and-response format used both in blues and jazz, can be traced back to the cultural and musical expression of Africa. The origins of the blues are also closely related to the religious music of the Afro-American community, the spirituals.
Blue notes (or "worried notes") are also an essential part of the sound. Blues shuffles or walking bass reinforce the trance-like rhythm and form a repetitive effect known as the groove.
Since the 1920s Jazz Age, Jazz has been recognized as a major form of musical expression in traditional and popular music, linked by the common bonds of African-American and European-American musical parentage.
As jazz spread around the world, it drew on national, regional, and local musical cultures, which gave rise to different styles. New Orleans jazz began in the early 1910s, combining earlier brass-band marches, French quadrilles, biguine, ragtime and blues with collective polyphonic improvisation.
In the 1930s, heavily arranged dance-oriented swing big bands, Kansas City jazz, a hard-swinging, bluesy, improvisational style and Gypsy jazz (a style that emphasized musette waltzes) were the prominent styles. Bebop emerged in the 1940s, shifting jazz from danceable popular music toward a more challenging "musician's music" which was played at faster tempos and used more chord-based improvisation.
Cool jazz developed near the end of the 1940s, introducing calmer, smoother sounds and long, linear melodic lines.
The mid-1950s saw the emergence of hard bop, which introduced influences from rhythm and blues, gospel, and blues, especially in the saxophone and piano playing. Modal jazz developed in the late 1950s, using the mode, or musical scale, as the basis of musical structure and improvisation, as did free jazz, which explored playing without regular meter, beat and formal structures.
Jazz-rock fusion appeared in the late 1960s and early 1970s, combining jazz improvisation with rock music's rhythms, electric instruments, and highly amplified stage sound. In the early 1980s, a commercial form of jazz fusion called smooth jazz became successful, garnering significant radio airplay.
Other styles and genres abound in the 2000s, such as Latin and Afro-Cuban jazz.