French Revolution

The French Revolution was a series of political and social upheavals which occurred in France between 1789 and 1799. This was the Doctor's favorite period of Earth history and one he visited on several occasions.

Revolutionary-era France was the site of the Doctor and Susan Foreman's first-ever visit to Earth. (NA: Just War). Later, while attending Coal Hill School in 1963, Susan borrowed a book about the French Revolution from her teacher, Barbara Wright, but noted that it had incorrect information on the first page. (DW: An Unearthly Child) Perhaps due to this, she decided to leave the book behind at school, where it would be found a few days later by Ace (DW: Remembrance of the Daleks)

The Doctor and Susan visited Revolutionary-era France again, this time with Ian Chesterton and Barbara Wright accompanying them, not long after departing 1963. (DW: The Reign of Terror)

Behind the scenes
The French Revolution was also a working title for The Reign of Terror.