States General was the representational assembly of the three estates. The clergy and nobility were privileged minorities, while the Third Estate represented the rest of the people.
During the last meeting of the Estates General, at the beginning of the French Revolution (1789), the Third Estate worried that the two privileged estates would overcome the general public in its effort to establish a reform.
Therefore, the revolutionary National Assembly was created, putting an end to the representation by social classes.
The purpose of the march was to advocate for the civil and economic rights of African Americans. At the march, final speaker Dr. Martin Luther King Jr., standing in front of the Lincoln Memorial, delivered his historic "I Have a Dream" speech in which he called for an end to racism.