Giordano Vitale

Giordano Vitale, also called Vitale Giordano or Vitale Giordani, was an Italian mathematician born at Bitonto in the Kingdom of Naples, probably on 15 October 1633, and dying on 3 November 1711. After an adventurous youth that included service as a soldier in the Pontifical army, he read his first mathematics book, Clavius's Aritmetica prattica, and at twenty-eight, living in Rome, devoted himself to mathematics, studying chiefly Euclid's Elements in Commandino's Italian translation. In Rome he befriended Giovanni Borelli and Michelangelo Ricci and was employed for a year by the former Queen Christina of Sweden. In 1667 he became lecturer in mathematics at the French Academy in Rome and in 1685 gained the chair of mathematics at the Sapienza University. He is best known for his theorem on Saccheri quadrilaterals, proved in his 1668 book Euclide restituto, a copy of whose second edition he gave to Leibniz when they met in Rome in 1689 or 1690.