On June 17 the Third Estate had decided to break away from the Estates General and make up their own Constitution. They made themselves the "National Assembly," on June 20, 1789. They had been locked out of their regular meeting place, when the Third Estate went to the place where they usually meet King Louis had locked them out and there had been guards there watching it so they couldn't get in. Third Estate had then met up in a tennis court nearby. They would continue to meet there until they had established the constitution of France. The Third Estate would continue to protest until they got representatives. The Third Estate was led by Compte De Mirabeau. This Oath would prove to the Third Estate as a step of protest that would lead eventually more power to the Estates General. The Oath had all indicated for the first time that French citizens formally stood in disapproval to King Louis XVI and would not refuse to back down the Kings confessions.
They got locked out of their original meeting room by King Louis XVI.
So the Third Estate had went to a tennis court near by.
The Oath had been signed by 576 out of the 577 people