As a solo artist, Diana Ross is one of the most successful female singers of the rock era. If you factor in her work as the lead singer of the Supremes in the 1960s, she may be the most successful. With her friends Mary Wilson, Florence Ballard, and Barbara Martin, Ross formed the Primettes vocal quartet in 1959. In 1960, they were signed to local Motown Records, changing their name to the Supremes in 1961. Martin then left, and the group continued as a trio. Over the next eight years, the Supremes (renamed "Diana Ross and the Supremes" in 1967, when Cindy Birdsong replaced Ballard) scored 12 number one pop hits. After the last one, "Someday We'll Be Together" (October 1969), Ross launched a solo career.