Big band music is characterized by swing music that had been orchestrated around the 1920s for large ensembles (early on, exclusively by blacks, but later by whites as well).
The music of the Big Band era originates from the fusion of the large ensembles of the predominantly white classical music genre with the predominantly black blues and gospel music. With the introduction of the swing era (and swing dancing) the music became more oriented around dancing.
With the economic depression of the 1930s, the capacity to financially support large orchestrated bands became difficult, and resulted in the adaption of smaller Jazz combos, bringing on the musical era known as "Bebop Jazz" in the 1940s.
Big band music was most popular around the 1920s, particularly when the dance craze known as "swing" came about, as the dance craze was particularly fundamental in introducing big band music to white audiences.
The most notable characters of the Big Band era include Duke Ellington, King Oliver, Louis Armstrong, Fletcher Henderson and Cab Calloway.