History of Rap and Hip Hop Culture

Compare two different hip hop/rap artists from two different periods at lease a decade apart (e.g. 70s, 80s, and 90s to the present)
Discuss similarities, differences, point of view in general
Then compare one songs by each artist and discuss the similarities/differences in lyrics, message, music influences and techniques used in lyrics (rhyme, form and content) and music
How do their individual backgrounds influence their music?
Do you hear any influences from other artists?
If so which artists?
Include lyric sheets attached as PDFs only.