In 1985, Disney released its 25th feature-length animated film, The Black Cauldron. The film was based on the book series The Chronicles of Prydain by Lloyd Alexander and featured a dark tone reminiscent of the Night on Bald Mountain sequence in Fantasia (1941) decades earlier. The fantasy epic was rife with production struggles, and Disney released a number of other films during its development, such as The Rescuers and The Fox and the Hound. Overall, it took over ten years for the film to be produced. But the animators working on it believed so much in its potential success it remained on the docket despite the continual delays. Even when production stalled as artists struggled to accurately animate the human characters.
Source：https://www.cbr.com/disney-black-cauldron-live-action/
