What mainstream jazz relied heavily on arrangement?

Mainstream jazz that relied heavily on arrangement includes big band jazz, especially during the Swing Era of the 1930s and 1940s. This style featured large ensembles with written scores that organized sections of brass, woodwinds, and rhythm, emphasizing complex arrangements and orchestrations. Notable bandleaders like Duke Ellington and Count Basie crafted intricate compositions that showcased both individual soloists and the cohesive sound of the ensemble. This reliance on arrangement distinguished big band jazz from more improvisational forms of jazz.