Pedro de Medina


Pedro de Medina was a Spanish cartographer and author of navigational texts. His well-known Arte de navegar was the first work published in Spain dealing exclusively with navigational techniques.

Early life

Medina is believed to have been born in Seville, although based on his name and the protection afforded to him by the Dukes of Medina Sidonia he may instead have been born in Medina-Sidonia. In 1520 he became tutor to Juan Claros Pérez de Guzmán y Aragón, the Count of Niebla and heir to Juan Alfonso Pérez de Guzmán, 6th Duke of Medina Sidonia.

Navigational science and cosmography

Earlier career

After having amicably parted from the House of Medina Sidonia, he sought recognition as a cosmographer and brought out a text titled Libro de Cosmografía. He received official permission to compile navigation maps, to write books about pilotage, and to manufacture navigational devices necessary for voyages to the Indies. In February 1539, he was appointed in Seville as examiner of the navigators and ship's captains who would take part in the conquest of the Indies. His work was closely associated with the "House of Trade", the Spanish government agency overseeing the exploration and colonization of the New World, although he never succeeded in gaining employment in that agency. He soon became aware of defects in the training of navigators and in the instruments, books and maps they relied upon, and wrote a "Representation" to King Charles I on the subject. This was the culmination of his rivalry with the cartographer Diego Gutiérrez and his family, who had the support of John Cabot. Medina's letter quickly led to a royal command of 22 February 1545, banning Gutiérrez from continuing to issue maps and instruments that Medina had described as very harmful to the students.

''Arte de navegar''

In 1545 Medina published his most important work, Arte de navegar in eight volumes. It was dedicated to the future Philip II, in support of his quest to be appointed royal cosmographer. This work was an overview of existing knowledge on this subject, and was probably a revision and expansion of his "Book of Cosmography", which had already been examined by the Council of the Indies. Arte was the first treatise on navigation to be published in Spain. The senior cosmographer Alonso de Chaves demonstrated that Medina's Arte was a compilation, made with the assistance of other writers. Diego Gutiérrez and other authors claimed that they had helped with parts of the book, and Medina himself acknowledged the assistance of Francisco Faleiro and Alonso de Santa Cruz on other occasions, but not with the writing of Arte. The book was internationally disseminated and quickly translated into several European languages: it was translated into French fifteen times between 1554 and 1663, five times into Dutch, three times into Italian and twice into English. This work contributed considerably to the development of navigation on the high seas.

Later career

In 1549 Medina achieved appointment as honorary royal cosmographer. An abridged edition of Arte in Spanish was published in 1552 under the title Regimiento de navegación, omitting most of the theory of spherical geometry and including only what was essential for navigators. A later edition of Regimiento updated this popular handbook and added twenty "warnings" for the practical navigator. His unpublished Suma de Cosmographia of 1561 is an abridged version of Arte de navegar, containing information on astrology and navigation and written for a nonspecialist audience.
Medina's work adhered to the cosmological system of Ptolemy rather than that of Copernicus. Despite his knowledge and achievements Medina continued to deny the phenomenon of magnetic declination, of which he lacked personal experience, in opposition to the opinion of most other cosmographers of the time.
Medina acted as royal adviser during the two assemblies convened by the Council of the Indies in 1554 and 1556 to determine the precise position of the Philippines and the Moluccas, and to define the demarcation between Spanish and Portuguese control in that part of the world. Mount Medina in Antarctica is named in his honour.

Other works

Medina also wrote historical and philosophical books. In 1548 he published a work titled Libro de las grandezas y cosas memorables de España. This dealt with historical acts and important towns in Spain, with engravings and transcriptions of key documents. It was later revised and expanded by Diego Pérez de Mesa, professor of mathematics at the University of Alcalá. Other works included Libro de la verdad, written in furtherance of disputes with the Casa de Contratación, and his last work,.

List of works