Pierre de Fermat

Pierre de Fermat was born on 17 August 1601 and spent his professional life as a magistrate at the parlement of Toulouse, a poet and classicist who happened to be one of the sharpest mathematical minds in Europe. He developed a technique called adequality that anticipated differential calculus, discovering methods to find maximum and minimum points on curves decades before the field formally existed. His work spanned analytic geometry, probability, optics - where his principle for light propagation still bears his name - and especially number theory, where he made contributions that would define the discipline. In a margin note in his copy of Diophantus' Arithmetica, he claimed to have proven a theorem about integer solutions to certain equations, adding that the margin was too small to contain his proof; that assertion became Fermat's Last Theorem, unproven until 1994. He died on 12 January 1665, having shared most of his discoveries through letters rather than formal publications, a hobbyist who quietly laid groundwork for centuries of mathematics.