Who is Django and why is he 'unchained'?

Jamie Foxx's character was named after a '60s spaghetti-western gunslinger.

Quentin Tarantino typically draws inspiration from an array of sources for his films, and "Django Unchained" is no exception. The title character gets his name from the 1966 spaghetti Western "Django," about a coffin-dragging gunslinger played by Franco Nero,who has a cameo in last year's film. Tarantino also may have drawn inspiration from another Italian film, 1959's "Hercules Unchained." And depending on how deep you want to go, there's a theory that Foxx's blue suit and the title are a combined tribute to the inventor of an early 20th-century camera technique.
originally found:   http://movies.yahoo.com/photos/oscars-2013-meanings-behind-oscar-movie-titles-explained-1361045867-slideshow/