Which real historical event begins Assassin's Creed Unity's main story?

The French Revolution begins the main historical setting of Assassin's Creed Unity.

Unity follows Arno Dorian in France as revolutionary upheaval transforms Paris. The game opens in the years before the Revolution and then moves into the period of major events beginning in 1789. Political instability, violence, factional conflict, and the changing relationship between social classes shape the missions and the city around Arno.

The American Revolution is the principal historical backdrop of Assassin's Creed III, while the Industrial Revolution provides the setting for Assassin's Creed Syndicate. The Seven Years' War is especially important to Assassin's Creed Rogue and parts of Assassin's Creed III. Unity uses real figures and locations from revolutionary France, but its Assassin and Templar plot is fictional and should not be treated as a literal account of the Revolution. The game was released in 2014 and was developed primarily by Ubisoft Montreal.