William Russell and Jacqueline Hill were supposed to cameo as Ian and Barbara at the end of the episode as they witness The TARDIS de-materialise after Dodo enters.
First appearance of Dodo.
This episode takes place in Paris, France in August 1572.
This episode was wiped by the BBC and no copy of it is known to exist.
The TARDIS prop was required out on location for the end of the episode, but it was also needed back in the studio for some other shots and so the decision was made to split the prop apart. The front wall section would go out on location, while the rest of it remained back at the studio for other recording needs. A set of mock up pieces were constructed to "complete" the prop for location - this included a set of very basic (and highly inaccurate) walls and windows, a base and an oversized roof.