I was slightly mistaken above when I dated what I consided Rap's earliest proponents being in the 70's. The Last Poets who I refered to started performing in 68' & are still on the scene. They were great at what they did, back then & now & were by far, way ahead of their time, really coming out of the civil rights era of protest. I still say that they perform a non musical style of a performing art. To me it's still poetry with a beat behind it but if you're interested in Rap's birth these are the guys to check out.
As always Azizi, you have a wonderful way with presenting information in such an appealing way, it's a joy to read your posts, thanks

Barry