Decline of an Empire is a 2014 British biographical historical drama film, produced and directed by Michael Redwood, about the life of Catherine of Alexandria.

The film originally carried the working title Katherine of Alexandria.

The film was also released direct-to-DVD in the United Kingdom on 6 April 2015 as Fall of an Empire: The Story of Katherine of Alexandria.

The latest version of the film is titled 'Katherine of Sinai' and was released in 2018 on streaming (Amazon Prime).

The Guardian awarded the film one out of five stars: "Fall of an Empire: The Story of Katherine of Alexandria review – a Roman epic on a British budget".