Pierre de Fermat
Pierre de Fermat (1601–1665). French judge and amateur mathematician. His little theorem has proved to be very useful in the study of prime numbers and in cryptography. His famous conjecture, for which he claimed to have found a proof too long for a margin, for three centuries drove mathematicians to advancements in mathematics in attempts to prove it.
- O'Connor, John J.; Robertson, Edmund F., "Pierre de Fermat", MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Fermat.html .