Blues has its roots in the plantation work songs of the slavery era. Banned from playing their own traditional music or practicing their religion, enslaved people created new songs. Based around the pentatonic tonal scales of their West African heritage, the lyrics praised the Christian religion of their captors, ensuring it was allowed to remain part of the new American cultural mix. An early form of guitar -- referred to as a "diddley-bow" or "Jitterbug" -- was based on a traditional African instrument, and consisted of a plank of wood, often mounted to the side of a house, with a single string nailed to it. This was played with a piece of metal or glass, much like modern slide guitar. The instrument later gave its name to seminal bluesman Bo Diddley.
The majority of conservative whites in America frowned upon Jazz and Blues, and saw them as a threat to the values that they wished to promote. The bawdy lyrics, and the salacious dancing that often went along with the upbeat rhythms were seen as a corrupting influence that should be kept from the American public, particularly its youth. But the conclusion of the First World War saw an explosion of hedonism in those lucky enough to survive. There was a focus on the pursuit of happiness and a willful disregard for consequences and staid tradition. Young Americans embraced the vibrant, energetic expressions of Jazz and Blues, giving birth to the "Flapper" craze. It's been suggested that the experience of the War allowed many whites to identify with the hardships expressed in "black music."
Prohibition was a boon for Jazz and Blues music. The illicit "Speakeasies," that sprung up to provide the well-heeled public with bootleg booze, provided a network of venues for bands and singers to ply their trade. The majority of Jazz and Blues luminaries of the time were predominantly black people, not permitted in the upscale theaters of big cities. The network of "Speakeasies" provided the new musicians with a broad audience from a variety of backgrounds and the opportunity to play in unfamiliar cities.
The 1920s saw the birth of audio recording as a genuine industry rather than a scientific plaything of the wealthy. Jazz and Blues artists began to make records which could then be distributed all over the world. They were among the first artists to ever build popularity in this way. Prior to this, artists could only build a reputation and a following through live performances. The early '20s saw the first recordings by "Empress of The Blues" Bessie Smith, and a young cornet soloist named Louis Armstrong.