Pierre de Fermat ( 17 August 1601 or 1607/8 – 12 January 1665) was a French lawyer at the Parlement of Toulouse, France, and an amateur mathematician who is given credit for early developments that led to infinitesinal calculus, including his adequality. In particular, he is recognized for his discovery of an original method of finding the greatest and the smallest ordinates of curved lines, which is analogous to that of the then unknown differential calculus, and his research into number theory. He made notable contributions to analytic geometry,probability, and optics. He is best known for Fermat's Last theorim, which he described in a note at the margin of a copy of Diophantus' Arithmetica.For more information click here