On June 25, 1949, Billboard Magazine introduced the term rhythm 'n' blues to refer to black popular music intended for distribution in black communities, formerly known as "race records." This taxonomy propagated myriad assumptions about the place and peculiarity of black music. Billboard's segregation of black music within the industry in 1949 was instituted in the midst of Jim Crow segregation, and the Civil Rights Movement's battle against it. By the end of World War II, R&B encompassed the genre's traditional quartets and soloists, and black rock and roll. As black music became a national cultural institution, the industry remained segregated. In the context of the Civil Rights and Black Power movements, the nuanced meanings of black music—especially R& B and Soul—would become more relevant than ever. The 1940s and 1950s pop balladeers and teenage groups combined idealism with political irony. Yet by the mid-1950s black rock would cause a more imminent threat to white sexual paranoia. Musicians including Chuck Berry would be targeted with criminal charges; racial violence would pervade black rock performances. 1960s soul would present perhaps the most adamant political messages of political justice. Figures including Marvin Gaye, Nina Simone, and Aretha Franklin would use their stage to expose an ardent demand for freedom.