Pacioli, Luca

(ca. 1445-1517)

   Italian mathematician and teacher. Born at Borgo San Sepolcro in Tuscany, he became a tutor to a wealthy family in Venice and developed his mastery of mathematics under a local teacher. By 1475 he was a teacher at the University of Perugia. About this time he became a Franciscan friar and continued to teach mathematics at various places. He was a friend of at least two major artists, Piero della Francesca and Leonardo da Vinci, both of whom had a strong interest in mathematics. He published several books, including Summa de arithmetica, geometría, proportione et proportionalità / A Summary of Arithmetic, Geometry, and Propor-tion (1494), a Latin edition of Euclid's Elements (1509), and a book De divina proportione / On Divine Proportion (1509), an expanded version of a work written collaboratively with Leonardo and illus-trated by him. The Summa was an important book, combining the in-tellectual mathematics of the academic tradition with the practical mathematics of the abacus, and showing a sophisticated grasp of al-gebra. It is also significant because it contains the first printed de-scription of the method of double-entry bookkeeping that Italian mer-chants had developed during the two preceding centuries.