Rock and roll is a genre of popular music that evolved in the United States during the late 1940s and early 1950s. The origins of rock and roll are rooted in a blending of African-American musical genres, mainly rhythm and blues, with stylistic influences from gospel, jazz, boogie-woogie, electric blues, jump blues, swing, and folk music. While rock and roll's early elements can be heard in blues records from the 1920s and in country records of the 1930s, the genre did not acquire its name until 1954.