Louis XVI and the Tennis Court Oath
In order to resolve the crisis, Louis XVI convened the long-dormant Estates-General, a national assembly divided into three orders based on social class: clergy (First Estate), nobility (Second Estate), and commoners (Third Estate).
Despite representing approximately 98 percent of the population, the Third Estate could be outvoted by its two counterparts. As a result of this disparity, its deputies immediately began clamoring for more power. After failing to make any progress, they declared themselves to be a new body called the National Assembly.
On June 20, 1789, they convened in a nearby indoor tennis court after discovering the doors to their meeting place locked. There, they swore an oath in defiance of the king to never part ways until creating a newly written constitution. This oath became known as the Tennis Court Oath.