In the '60s, when the rest of the world was in upheaval, R&B evolved too, garnering influences from country, gospel, and rock—and soul music was the result. First-gen soul singers like Otis and Aretha came up in the civil rights era, when African-Americans needed a sound that dug deeper than ever into, well, the soul. Funkier, more fervent, and more sensual than anything in R&B's past, the music mutated over the decades. Artists like Marvin Gaye, who became famous crooning love tunes in the mid ‘60s, started spinning socially conscious messages in the ‘70s. Likewise, the seeds people like James Brown sowed early on eventually sprouted into a full-blown funk revolution. The tree grew different branches with each successive generation, such as the smooth Philly soul of the '70s and the organic neo-soul of the '90s, but the music always retained its intense emotional core.