Prequel Trilogy
From Ewokpedia
A trilogy of films rumored to be set before the events of Star Wars 1: The Phantom Menace. George Lucas is rumored to have planned the Star Wars saga as a set of three trilogies, Star Wars 1-3, Star Wars 4-6, and a final set of movies centered around the early lives of Yoda, Palpatine, and Darth Maul.
Despite much fan anticipation and the release of promotional materials including film trailers, action figures and videogames, no prequel trilogy was ever actually released to theaters.