Pierre de Fermat (August 17, 1601 – January 12, 1665) was a French lawyer at the Parliament of Toulouse and a mathematician who is given credit for the development of modern calculus. In particular, he is the precursor of differential calculus with his method of finding the greatest and the smallest ordinates of curved lines, analogous to that of the then unknown differential calculus. Perhaps even more important, his brilliant researches in the theory of numbers entitle him to rank as the founder of the modern theory. He also made notable contributions to analytic geometry and probability.
Fermat worked on number theory while preparing an edition of Diophantus, and the notes and comments thereon contained the numerous theorems of considerable elegance necessary to develop the theory of numbers. Fermat is famous for his "Enigma" that was an extension of Pythagorean Theorem, also known as Fermat's last theorem, which baffled mathematicians for 300 years, and was only finally proved in 1994. Together with René Descartes, Fermat was one of the two leading mathematicians of the first half of the 17th century. Independently of Descartes, he discovered the fundamental principle of analytic geometry. Through his correspondence with Blaise Pascal, he was a co-founder of the theory of probability.
Fermat was born at Beaumont-de-Lomagne, 58 kilometers (36 miles) north-west of Toulouse, France. He died at Castres, 79 kilometers (49 miles) east of Toulouse. The oldest and most prestigious high-school in Toulouse is called Pierre de Fermat. This high-school has also preparatory classes for engineering and business schools (grandes écoles), and is ranked in the top 10 of France's best preparatory classes. The late 15th century mansion where Fermat was born in Beaumont-de-Lomagne is now a museum.