Cynthia Robinson, who co-founded Sly and the Family Stone and was the group's trumpeter, died Monday after battling cancer, according to a post on her Facebook page. Born in Sacramento, Calif., Robinson's first taste of music came through playing in her high school marching band and singing in her church's choir. The Cynthia Robinson Cancer Care Fund had recently been established to help Robinson's "rising medical costs," the administrator of her Facebook page wrote.