Which influential pamphlet was published by Abbé Sieyes?

The pamphlet published by Abbé Sieyes titled "What is the Third Estate?" played a crucial role in shaping political thought during the early stages of the French Revolution. Sieyes argued that the Third Estate, which comprised the vast majority of the population including peasants, workers, and the bourgeoisie, was essential to the nation’s prosperity and identity, yet it was burdened by the privileges of the First and Second Estates (the clergy and the nobility).

The pamphlet effectively challenged the existing social structure by asserting that the Third Estate was not only the most significant group but also the source of legitimacy for the French state. Through this work, Sieyes called for the Third Estate to gain political representation and power, paving the way for the revolutionary changes that followed. The pamphlet helped to galvanize public opinion against the privileges of the aristocracy and to promote the idea of equality among citizens, which was central to the revolutionary ideals of the time.