A prodigy in math, Blaise Pascal was a contemporary and rival of René Descartes. In spite of years of ill health and a short life, Pascal accomplished quite a bit: he published a significant work on the geometry of conical sections when he was only sixteen; he invented a calculating machine by the time he was nineteen; he and Pierre de Fermat founded the modern theory of probability; he described the principle that is the basis for the hydraulic press (called Pascal's Law); and he proved that there was a vacuum above the atmosphere. Pascal had a religious conversion in the 1650s and devoted himself to religion instead of science. He is famous for the philosophical theorem known as Pascal's Wager, and for the remark that history would have been different had Cleopatra's nose been differently shaped.