The origins of rock and roll are complex. 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, the beat-heavy jump blues, boogie woogie, up-tempo jazz, and swing music. It 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 simply as rock music. The phrase "rocking and rolling" originally described the movement of a ship on the ocean, but it was used by the early 20th century, both to describe a spiritual fervor and as a sexual analogy. Various gospel, blues and swing recordings used the phrase before it became used more frequently – but still intermittently – in the late 1930s and 1940s, principally on recordings and in reviews of what became known as "rhythm and blues" music aimed at black audiences. In 1939 during the April 5th broadcast on “The Fred Allen- Town Hall Tonight- Show” the song “Rock and Roll” appeared as a barber shop quartet lead-in. In May 1942, long before the concept of rock and roll had been defined, a Billboard record review described Sister Rosetta Tharpe's vocals on the upbeat blues song "Rock Me", by Lucky Millinder, as "rock-and-roll spiritual singing". In 1951, Cleveland-based disc jockey Alan Freed began playing this music style while popularizing the term "rock and roll" on mainstream radio. As a 2018 BBC article explained, "by the time DJ Alan Freed started using the term to describe ... rhythm and blues ... the sexual component had been dialled down enough that it simply became an acceptable term for dancing". Freed was the first radio disc jockey and concert producer who frequently played and promoted rock and roll, including songs by black artists that were considered to be R&B. Various recordings that date back to the 1940s have been named as the first rock and roll record, or at least as precursors of the music. The term "rock and roll" Early usage of the phrase The alliterative phrase "rocking and rolling" originally was used by mariners at least as early as the 17th century to describe the combined "rocking" (fore and aft) and "rolling" (side to side) motion of a ship