ENSPM2021 Talk

Title: The Moluccas question: Ptolemaic cartography versus nautical charting.

Abstract: In the aftermath of the return of Magellan’ expedition in 1522, a major diplomatic dispute erupted between Portugal and Castille. At the core of the dispute was a scientific and geographical issue: the location of the Moluccas islands. When cosmographers and mathematicians of both kingdoms looked into the matter, they realized that the issue was much more complex and subtle than anticipated. Naturally, it required the measurement of longitude; but, very surprisingly, it revealed the unexpected complexity of the geometry of nautical charts and the fact that nautical charting was incompatible with the prescriptions of Ptolemaic rules for making maps.

Henrique Leitão (University of Lisbon, Portugal)

Portuguese historian of science, presently chair of the Department for History and Philosophy of Science at the University of Lisbon. After initial studies in theoretical Physics (PhD, 1998), directed his interests to the history of science. Has published extensively in the history of exact sciences in Europe from the 15th to the 17th century and was the head of the scientific committee in charge of the publication of the Complete Works of the sixteenth-century mathematician Pedro Nunes (Lisbon Academy of Sciences and Calouste Gulbenkian Foundation). Also interested in the history of scientific books and ancient scientific libraries, he is member of various learned societies, including the Academia das Ciências de Lisboa (Lisbon Academy of Sciences) and the Académie Internationale d’Histoire des Sciences. Henrique Leitão is one of the most respected and popular scientists in Portugal and as a consequence received in 2014 the Prémio Pessoa, one of the highest prizes a Portuguese can win, and in 2015 was decorated by the President of the Republic with the Comenda da Ordem de Sant’Iago da Espada, for outstanding achievements in science; he received also an ERC Advanced Grant, in 2019. More info >