It unusually, though certainly not without precedent, dealt with Christianity's early history. It was also a particularly strong story for Erimem, who came close to leaving the Fifth Doctor over the morality of preserving the integrity of the timeline. In this conflict, the fact that Erimem came from an even more distant past than the story's setting of 325 AD was of central importance. Unlike most stories featuring an "historical companion", the fact of her origin, both as a former Pharaoh and an ancient Egyptian, fully mattered to the progress of the narrative.