Who was the one who first stated the law of definite proportions?

Law of definite proportions:

• A French chemist Joseph-Louis Proust first proposed the Law of definite proportion.
• According to the law of definite proportion, constituent elements of a compound always remain in a fixed ratio (by mass) and are unaffected by its origin or manufacturing process.
• The law is the foundation for chemistry's study of stoichiometry.