In Assassin's Creed Unity, which historical event begins Arno Dorian's childhood backstory?

The assassination of his father begins Arno Dorian's childhood backstory in Assassin's Creed Unity.

Arno is introduced as a young boy who loses his father, Charles Dorian, during an assassination in Versailles. After Charles dies, Arno is adopted by François de la Serre, the Grand Master of the French Templars. This unusual upbringing places Arno inside a Templar household even though he later joins the Assassins.

François de la Serre is also assassinated years later, and Arno is blamed because he was responsible for delivering a message connected with the event. His imprisonment and subsequent escape lead him toward the Assassin Order and the central conspiracy of the game.

Unity is set during the French Revolution, but the storming of the Bastille occurs after the childhood incident. The execution of Louis XVI is later still. Those events form the historical backdrop, while the assassination of Charles Dorian is the personal event that starts Arno's story.