Who was David Wark Griffith?

Griffith was a filmmaker whose seminal work, "The Birth of a Nation," provides a crowning achievement in early cinematography and editing. (This film is marred, however, by its extreme racial prejudice.) His work was popular in the early days of the film industry, though, and his success led to the production company for which he worked to start taxing theaters to show their films. However, as film production moved out to California, Griffith started to discover actors with an immense talent for conveying emotions for the audience.