When did Mississippi Delta blues first develop?

Mississippi Delta blues is a regional style of American folk music that developed in the Delta region of northwestern Mississippi by at least the turn of the 20th century.12

While no commercial recordings of the style were made until the late 1920s, scattered accounts from travelers and researchers confirm its presence in the region during the early 1900s. For example, the composer W.C. Handy documented an encounter with the music around 1903 at a train station in Tutwiler, Mississippi, where he observed a musician playing guitar with a knife—a technique now recognized as a hallmark of the Delta sound.2