David Whitaker was, by this time, seeing stories with historical figures as a liability. Despite this, the story was intended as the third of three historical tales, following the Spanish Armada and the American Civil War. It appears to have been Verity Lambert who convinced him to script this story as a comedy.
Dennis Spooner's original idea was to spoof Quo Vadis (1951), which led him to choosing the time of the Great Fire of Rome as his setting.
This was also the first time a major actor requested to be on Doctor Who (1963). Here, Derek Francis was given the role of Nero.