The term blues may have come from "blue devils", meaning melancholy and sadness
The roots of the blues are to be found among the songs of the community of African-American slaves in the plantations of the southern states of the United States of America (Cotton Belt).
Fundamental was the year of the abolition of slavery in the United States of America (1865) when granted freedom, many ex-slaves musicians started to take their music out of the plantations and, in a few decades, this genre became known.
The musicians who created the blues had no formal education and could not read and write. Improvisation, oral and written, played an important part in this musical form.
The lyrics of early traditional blues verses probably often consisted of a single line repeated four times. The subject is always intensely personal, and normally melancholy.
The tool that was used by the first musicians blacks freed from slavery (except for the rubber band nailed to the table) was the cigar box, a kind of guitar that as the body had a box of cigars, or wood or metal containers.
Jazz was born as vocal music that was performed at work on plantations or during railway construction and roads, this to give rhythm and coordinate labor movements.
It develops in the early twentieth century in New Orleans, Louisiana, quickly establishing itself as a combination of several musical cultures.
The main elements of jazz are two: the rhythm and improvisation.
The original jazz music was based on combinations of African musical elements, mixed with harmonies derived from European classical music.
All the jazz music has been described as cultured because it is resulting knowledge of classical music, music of various ethnicities and complex harmonic developments.
The same can not be said for the original blues.
The most frequent combination is the quartet, almost invariably consists of drums, bass or contrabass, piano and a solo instrument, generally a saxophone or a trumpet.