This episode was wiped by the BBC and no copy of it is known to exist.
William Hartnell disapproved of some dialogue implying an incestuous relationship between Richard and Joanna. The offending material was removed.
This episode takes place in Palestine in 1190.
This was the first of two William Hartnell serials that Jean Marsh had starring roles in. The other was "The Daleks' Master Plan".
This episode was watched by 8.5 million viewers on its original transmission.