The 25-minute film was directed by Roger Christian, who earned an Oscar for set decoration on the original Star Wars. It tells the story of a knight returning home from the Crusades who gets lost in a fantasy realm.

George Lucas wanted a film to play ahead of Empire, and commissioned Black Angel after hearing Christian's pitch. Christian took £25,000 and headed to Scotland with a crew of nine people, four actors and two horses.

See more Meet the 'Star Wars: Episode VII — The Force Awakens' Cast (Photos)

Though it was lost shortly after leaving theaters, the film made its mark on other projects. Director John Boorman showed his Excalibur crew Black Angel, and Lucas liked Christian's technique of step-print slow motion for the fight scenes, and used it in an Empire Strikes Back scene.

Christian screened the film at two festivals last year, and is making the film available for free on YouTube for the rest of the month.