<P> 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 simply as rock music . </P> <P> 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 1951, Cleveland - based disc jockey Alan Freed began playing this music style while popularizing the term "rock and roll" to describe it . </P> <P> Various recordings that date back to the 1940s have been named as the first rock and roll record . </P> <P> 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 on the ocean . Examples include an 1821 reference, "...prevent her from rocking and rolling ...", and an 1835 reference to a ship "...rocking and rolling on both beam - ends". As the term referred to movement forwards, backwards and from side to side, it acquired sexual connotations from early on; the sea shanty "Johnny Bowker" (or "Boker"), probably from the early 19th century, contains the lines "Oh do, my Johnny Bowker / Come rock and roll me over". </P>

When was the first rock and roll song made