Pietro Antonio Cataldi

1548-1626

Italian Mathematician

In the course of a career that spanned more than six decades, Pietro Antonio Cataldi made contributions in a number of areas. Not only was he one of the first mathematicians to work on continued fractions or infinite algorithms, providing definitions, common forms, and symbolism, but his research in algebra and perfect numbers, as well as his extensive writing and editing of texts, added greatly to the sum of mathematical knowledge. In his will, the unmarried Cataldi requested that a school of math and sciences be established in his home, a wish that went unfulfilled.

Cataldi, who was born in Bologna on April 15, 1548, studied at the Academy of Design in Florence before going to work as a math instructor at age 17. He continued in this position, lecturing in Italian rather than Latin (the accepted language of scholarly discourse at that time), until his early to mid-twenties. From 1570 or 1572 until 1584, he taught at the University of Perugia and the Perugia Academy; then he returned to Bologna at age 36, at which point he received his diploma. It was around this time that Cataldi—who would publish more than 30 books during his career—began his most important writing.

Practica aritmetica, published in four parts between 1606 and 1617, was Cataldi's first significant published work. In a generous if perhaps eccentric gesture, he arranged for Franciscan monks to distribute copies of the book to poor children. Perhaps his most important work was Trattato del modo brevissimo di trovar la radice quadra delli numeri, which though he seems to have completed it in 1597, did not see publication until 1613. In Trattato, Cataldi employed infinite series and unlimited continued fractions to find a number's square root. This was perhaps the first serious examination of continued fractions on record.

In the area of applied mathematics, Cataldi—both in the Trattato and in other works—addressed the topic of artillery range. He also edited a 1620 edition of the first six books in Euclid's (c. 325-c. 250 b.c.) Elements. In latter years, he attempted to establish a Bologna mathematics academy, with uncertain results. He died in his home town on February 11, 1626.

JUDSON KNIGHT