Emmanuel Joseph Sieyès was born May 3, 1748, at Fréjus in the south of France. Although educated for priesthood at the Sorbonne, he embraced the works of writers such as John Locke.
Despite his passion for these secular philosophies, Sieyes entered the Church. At the time of the Revolution, Sieyes was an abbe, a designation for a lower-ranking clergyman in the French Roman Catholic Church. Sieyès presented his celebrated pamphlet, "Qu’est-ce que le tiers état?" (What Is the Third Estate?) to the Estates General in 1789. In this pamphlet, the liberal cleric, who was actually part of the First Estate, argued that the Third Estate was essentially the people of France.
The Third Estate subsequently invited members of the First (clerical) and Second (noble) Estates to join them. Sieyes famously did so, and his pamphlet essentially became the manifesto of the French Revolution. Sieyes also drafted the influential "Declaration of the Rights of Man and Citizen", and voted for King Louis XVI’s execution during the third National Assembly in September 1972.
During the Reign of Terror and installation of the Cult of Reason, the cleric Sieyès even denied his faith, later declaring he did so to survive. Sieyes was also publicly active during the Napoleonic era, and died in 1836.