Pierre Fermat (c. 1601–1665) has been called the greatest amateur mathematician. After growing up in Beaumont-de-Lomagne in Gascony (where his home now houses an interesting museum⋆⋆), he studied in Orléans and Toulouse, became “commissioner of requests” in 1631, and conseiller du roi in the local parlement, through which any petitions to the king had to pass. He died in Castres, where he was in the commission implementing the Édit de Nantes, which gave some protection to the persecuted protestant Huguenots. Fermat never left the area, never published a paper, and still became the second-best mathematician of his century (after Newton). Fermat communicated his mathematical discoveries in numerous letters, usually without proof and often in the form of challenges, to his contemporaries. (Among them was René Descartes, who could only be reached through his friend Marin Mersenne in Paris, because for many years he lived in Holland without a fixed address—a Flying Dutchman of mathematics, like the modern-day late Pál Erd˝os.)

Fermat was a pioneer in several areas. His method for drawing a tangent to certain plane curves was a step in the invention of calculus—later came Newton and Leibniz.