A photo of Professor Sir Andrew Wiles outside the Oxford University Mathematical Institute building, named in his honour. Three whole numbers a, b, and c form a Pythagorean triple if a2 + b2 = c2 (see the figure above); for example, 3, 4, and 5. There are infinitely many such triples. In 1637, Pierre de Fermat claimed that for every whole number n greater than 2, there are no whole numbers a, b, and c satisfying an + bn = cn. After several efforts by leading mathematicians, a proof was finally obtained by Wiles in 1994 and published in 1995 (Andrew Wiles, Modular elliptic curves and Fermat’s Last Theorem, Annals of Mathematics 142 (1995), 443-551). This is one of the biggest mathematical achievements and has been called the proof of the century.