Blaise Pascal
Blaise Pascal Mathematician Blaise Pascal was born on June 19, 1623, in Clermont-Ferrand, France. In the 1640s he invented the Pascaline, an early calculator, and further validated Evangelista Torricelli's theory concerning the cause of barometrical variations. In the 1650s, Pascal laid the foundation of probability theory with Pierre de Fermat and published the theological work Les Provinciales , a groundbreaking series of letters that defended his Jansenist faith. Pascal is also widely known for his body of notes posthumously released as the Pensées . He died in Paris on August 19, 1662.