Folha: ‘In Search of the Origins of Mathematician Pedro Nunes’
Reproduction of Marcelo Viana’s column in Folha de S. Paulo.
Pedro Nunes enrolled at the University of Salamanca at the age of 16, embarking on a brilliant career as a scientist and inventor that would make him the first full professor of mathematics at the University of Coimbra (in 1544) and tutor to several princes of the Portuguese royal family, including, most likely, the future (and ill-fated) King Sebastian.
Fluent in Latin and Spanish, in addition to his native Portuguese, he wrote several books in these three languages throughout his life. His first work, *Tratado da Esfera* (*Treatise on the Sphere*), published in Lisbon in 1537, includes translations into Portuguese and his own original texts on navigation.
Thirty years later, he published in Spanish in the city of Antwerp the *Libro de Algebra en Arithmetica y Geometria*, his major mathematical work—a text that was quite advanced for its time—in which he discusses the recent solution to the cubic equation and presents a systematic treatment of negative numbers.
That same year, he published *De Crepusculis* in Lisbon, a mathematical study of the night sky written in Latin, one of his most original works. In it, he describes his most famous invention, called the nonius—a system of two juxtaposed sliding scales with slightly different graduations that greatly increased the precision of measurement. We know that the vernier was widely used at the time: one of its users was the great Danish astronomer Tycho Brahe, who even built two to incorporate into his astrolabes.
Retirement from the University of Coimbra was a painful experience. Disagreements over the calculation of length of service and the amount of his pension were only resolved through direct royal intervention, and even then, the university never fully complied with what had been determined, nor did it even consult him in the selection of his successor. Also plagued by family troubles, which I have already mentioned here, he ultimately died in isolation. But not in oblivion: his scientific contribution was remembered in virtually every text on mathematics published in Europe during the 1Fridays and 17th centuries.
But the great mystery surrounding Pedro Nunes concerns his origins. Aside from the fact that he was born in 1502 in the city of Alcácer do Sal, we know nothing about the years leading up to his arrival at the University of Salamanca, including who his ancestors were. In “Pedro Nunes: In Search of His Origins,” Portuguese historian Maria Teresa Lopes Pereira argues that Pedro Nunes’s own silence regarding his family background was intentional.
Six years before his birth, in 1496, King Manuel had signed the Edict of Conversion, which required every Jew who wished to remain in the kingdom (and retain his property…) to convert to Catholicism. This created the category of “New Christians”—Jews whose forced conversion was always a source of skepticism, which was, in fact, fully justified in many cases. Although they were theoretically on an equal footing with the “Old Christians,” the converts were systematically discriminated against.