The Spark: A Bankrupt Kingdom
By 1789, France was on the brink of collapse. Decades of war (including funding the American Revolution) and royal extravagance had drained the treasury. To resolve the crisis, King Louis XVI summoned the Estates-General, a legislative assembly that hadn't met in over 150 years.
French society was notoriously divided into three "Estates": the Clergy (First), the Nobility (Second), and the Commoners (Third). The Third Estate represented 98% of the population, including peasants, workers, and the wealthy bourgeoisie, yet they were consistently outvoted by the privileged orders.
Angry and demanding representation, the Third Estate broke away to form the National Assembly. Locked out of their meeting hall, they gathered on a nearby indoor tennis court and swore the famous Tennis Court Oath, vowing not to disband until they had written a constitution for France.