In Assassin's Creed Unity, what historical event begins Arno Dorian's main adventure?

In Assassin's Creed Unity, the French Revolution begins Arno Dorian's main adventure. The game is set in Paris from 1789 onward, as political upheaval, economic hardship, and conflict transform the city and its institutions.

Arno's personal story is connected to the Revolution through the death of his adoptive father, François de la Serre. He later joins the Assassin Brotherhood and investigates a conspiracy involving Templars and political power. The historical setting supplies famous locations and events, while the central Assassin-Templar plot remains fictionalized.

The American Revolution belongs primarily to Assassin's Creed III, whose protagonist is Connor Kenway. The Industrial Revolution is the setting of Assassin's Creed Syndicate, which takes place in Victorian London. The July Revolution occurred in 1830, decades after Unity's principal period, so it is not the event that launches Arno's story.