Rhythm and blues (R&B) is a type of music made popular by African Americans in the post-World War II period. R&B has many different definitions and interpretations and has been influential to other musical genres. It has branched off to create other forms of pop music, including rock and roll. Rhythm and blues has become a generic term to define music ranging anywhere from soul, funk, pop and contemporary R&B.
Read more : http://www.ehow.com/facts_4909904_did-rb-music-first-start.html