Stargate SG-1 follows and expands upon the Egyptian mythologies presented in Stargate the movie. In the Stargate universe, humans were enslaved and transported to habitable planets by the Goa'uld System Lords Ra and Apophis. For millennia, the Goa'uld harvested humanity, heavily influencing and spreading human cultures. As a result, Earth cultures are found throughout the known habitable planets of the galaxy.