Rock and roll emerged as a defined musical style in the United States in the early to mid-1950s. It derived most directly from the rhythm and blues music of the 1940s, which itself developed from earlier blues, boogie woogie, jazz and swing music, and was also influenced by gospel, country and western, and traditional folk music. Rock and roll in turn provided the main basis for the music that, since the mid-1960s, has been generally known as rock music.