Jason Gubbels provides an excellent overview of the music that served as the building blocks of the blues, which, by extension, made it the foundation for much of American popular music. You should check out the entire piece. He also points out that much of this music was marketed as blues when it originally was released following the turn of the century, but that twelve bar blues didn’t exist until the 20s. Quote:
- “Blues” itself became a hip marketing term attached to song titles in an attempt to stay current with an evolving musical culture, often taking the place of what before might have been “rag” or “stomp”…Many of these early blues performers were never strictly blues artists — Mamie Smith came out of vaudeville, Blind Blake picked ragtime guitar, and plenty of Mississippi Delta blues singers incorporated country music and current pop songs into their repertoire. So while we largely lack historical recordings demonstrating the origins of the blues, the reality is that plenty of blues performers continued to cut examples of pre- and proto-blues material during their recording sessions.