This is the fourth in a set of posts on editions of Sacrobosco’s Sphere produced in Spain and Portugal. The second translation of Sacrobosco’s Sphere into Spanish was made by the Jerónimo de Chaves (1523 – 1574), a mathematician, astronomer and cosmographer who held important positions at the House of Trade (Casa de Contratación). Jerónimo de Chaves’s sphere was called Treatise of the sphere composed by Doctor Johannes de Sacrobosco with many additions.  It was published in Seville in 1545.

Jerónimo de Chaves, Tractado de la sphera que compuso el doctor Ioannes de Sacrobusto con muchas additiones (Sevilla: Juan de Leon, 1545). Universidad Complutense Madrid.

As I noted in an earlier post, there were more translations of the Sphere into Spanish and Portuguese in the sixteenth and seventeenth centuries than into all other European vernaculars combined.  One reason for the interest in Sphere translations in Spain and Portugal was that the basic astronomical and geographical knowledge contained in this text could be used for navigation, and Spain and Portugal were engaged in voyages of exploration and colonization earlier than the rest of Europe.  Astronomical knowledge served vital state interests – and received state support – in a way that it did not in other parts of Europe.  As scholars such as Maria Portuondo, Antonio Barrera-Osorio and Alison Sandman have noted, the Spanish and Portuguese monarchs actively supported the development of cosmography, a subject that combined mathematics, astronomy and geography.  These intellectual disciplines were vital to the success of colonial operations.

In Spain, the University of Salamanca was a key site for the development of cosmography.  The curriculum included subjects like cartography, and incorporated information from voyages to the West Indies and the Americas.  Beginning in 1529, the University’s statutes specified that the mathematics professor teach arithmetic, geometry, astrology, perspective and cosmography.  This statute was instituted because the Spanish crown was concerned that there be enough men trained in cosmography, because the subject was critical for navigation and for the mapping of Spain’s overseas possessions.  The other state-supported institution in Spain that fostered the development of cosmography was the House of Trade (Casa de Contratación) in Seville.  This institution was founded in 1503 to coordinate and regulate commerce and navigation to the Americas and the Indies.  The House of Trade needed men who could prepare instruments and charts for navigation, teach methods of navigation, and make maps.  The House of Trade was responsible for licensing pilots, and administered an exam to make sure they knew how to use navigational instruments.  There were numerous navigation manuals produced in Spanish in the first half of the sixteenth century for pilots and navigators.  The House of Trades, unlike the University of Salamanca, brought together scholars and navigators, and sought to foster cooperation between those with theoretical expertise and those with practical experience.  However, the relations between these two groups were far from smooth.  Cosmographers promoted the use of astronomical instruments – most notably the astrolabe, which was used to find latitude at sea.  Navigators, on the other hand, preferred to use the compass and dead reckoning.  Use of the astrolabe required theoretical knowledge of astronomy, whereas use of the compass required practical experience.  Because Sacrobosco’s Sphere offered a basic introduction to astronomy, a number of cosmographers saw it as a valuable resource in convincing pilots, as well as royal and aristocratic patrons, of the usefulness of astronomical knowledge.

Jerónimo de Chaves (1523 – 1574) was the first Chair of Cosmography (Cátedra de Cosmografía) at the House of Trade. He was appointed in 1552, when the post was first created. Unlike later occupiers of the post, who were generally older and more experienced, Chaves was quite young (only 29 years old). He almost certainly got the post through the influence of his father Alonso de Chaves, who was appointed Pilot Major at the House of Trade in the same year his son was appointed Chair of Cosmography. The creation of the Chair of Cosmography was part of a several decades long power struggle between “practical” and “theoretical” men at the House of Trade. The practical men – pilots and navigators who had experience sailing – asserted that experience at sea, and the knowledge of local weather, wind, water and shore conditions was critical to successful navigation. The theoretical men – the cosmographers – by contrast, insisted that a thorough understanding of the positions and movements of celestial bodies was critical to navigating in unfamiliar locales. Social differences exacerbated these tensions, as the cosmographers came from more elite backgrounds and increasingly had university educations. Pilots and navigators came from artisanal backgrounds and were not always literate. While few would deny that both experience and theory were necessary, the relative weight to be assigned to each in the training and licensing of pilots was a point of serious disagreement. The creation of the Chair of Cosmography was a victory for the theoretical men. (On the debates between pilots and cosmographers, see Alison Sandman’s dissertation, especially chapter 4.)

When Jerónimo de Chaves was first appointed Chair, the course of instruction required for pilots was three years. In the first half of the first year, aspiring pilots were taught Sacrobosco’s Sphere and arithmetic.  In the second half of the year they read Georg  Puerbach’ Theorica and the Alfonsine Tables. In the second year, they went through the first six books of Euclid, Regiomontanus’ De triangulis omni modis, and Ptolemy’s Almagest. In the third and final year, future pilots studied cosmography and navigation, including the use of instruments like the astrolabe. However, a three-year curriculum was a tremendous hardship for men who made their living at sea. This ambitious program was rapidly shortened to several months. (This description of the curriculum is from Antonio Sánchez Martínez, pp. 138-9) Jerónimo de Chaves continued in his post and was involved in training pilots until 1568.

Jerónimo de Chaves, Chronographia o Reportorio de los tiempos, 1554. Colección: Libros electrónicos UCM-Google.

I will focus in the rest of this post on Jerónimo de Chaves’ translation of and commentary on Sacrobosco’s Sphere, but I note that he is perhaps better known for a later work, Chronographia o repertorio de tiempos, el mas copioso y precisso, que hasta ahora ha salido a luz, which went through twelve editions in his lifetime and a further ten after his death (several other editions are available online) (For more on this work, see Ursula Lamb). He also made maps, including maps of Florida.

Chaves’ translation of Sacrobosco’s Sphere contains quite extensive commentary. However, despite his later role as a teacher of navigators, the commentary contains very little directly related to navigation. In the prologue he claims that he chose to translate the Sphere, “for the pleasure and common usefulness of my country and my friends” (dela delectation y utilidad commun de mipatria y amigos). But he makes clear that he had far more in mind than the usefulness of this text as a basis for navigation. He claims that he wanted to make “the most sublime science and art of Astronomy” (tan sublimada sciencia y arte de la Astronomia), which reveals the “Majesty, Wisdom and infinite Power” (su Magestad, Saber, y infinito Poder) of the creator, accessible to those who could not read Latin. Chaves’ view of the “utility” (utilidad) of astronomy was quite broad. He asserts that the material in Sacrobosco’s Sphere was essential for philosophers, physicians and astrologers. It was also necessary if one wanted to comprehend “certain passages and obscure verses of poets” (algunos lugares y versos obscuros de Poetas). Here he seems to have had in mind primarily Virgil, whose Georgics is cited throughout the commentary, as well as Lucan. Navigation only comes in at the end of Chaves’ list of reasons for learning astronomy. There are only a couple of references in the entire book to “those who sail the Atlantic” (“Los que navegan el mar Oceano,” on fol. xxvii verso and fol. xxx). Very little material in the book touches on problems of navigation or cosmography relevant to exploration of the “New World.” Chaves includes a discussion of the location of the meridian at the “Fortunate Isles” (or the “Canaries”), a topic of much contention between Spanish and Portuguese cosmographers (on this controversy see Sandman’s dissertation, ch. 1) He includes a table of the positions of fixed stars, but does not include any “new” stars or constellations, like the Southern Cross (fol. xlviii – verso). Similarly, he includes a table of the longitudes and latitude of various places, but all in Spain, nothing in the “New World” (fol. l verso – fol. li).

“Table of latitudes and longitudes of some significant places in Spain”  fol. li.


While Chaves’ translation of Sacrobosco’s Sphere may well have appealed to people who could not read Latin (or who could not read Latin well), he had a more learned audience in mind as well. He claimed that his version of the Sphere had more extensive commentary, including “many demonstrations, figures and supplementary tables” (muchas demonstrationes, figuras y tablas supputatorias), than most other editions of Sacrobosco, even those in Latin. And indeed, his explanations and expansions on Sacrobosco’s original text are among the longest and most detailed that I have seen, and his text is one of the most richly illustrated.

Orb, fol. xi.

For example, to Sacrobosco’s description in book one of the spheres that make up the cosmos, Chaves adds a discussion on differences between orbs and spheres, complete with an image showing that the center of a sphere need not be the same as the center of a concavity inside that sphere. This preliminary explanation, and its accompanying image would certainly have been helpful to readers when they came to the orb models of the sun, moon and Mercury presented in book four.

Orb model of sun, fol. lxxxvi verso.


Chaves added to Sacrobosco’s treatment of the terrestrial realm in a number of ways. He claims that the sphere of air is actually divided into three different regions, the middle of which bulges rather than being perfectly spherical.

Regions of air, fol. xiii verso.

He gives dimensions for each part of the terrestrial realm:

If you want to find the diameter and circumference of all of the other elements, multiply them by ten of the earth. In this way, the water is ten times bigger than the earth; and the air is ten times bigger than the water and one hundred times bigger than the earth; and the fire is ten times bigger than the air, and a thousand times bigger than the earth.

El Diametro y ambito de todos los otros Elementos, si lo quisieremos hallar, sera multiplicando los por el diez tanto dela Tierra: de tal manera, que el Agua sea diez tantomas que la Tierra: y el Ayre diez tanto mas que el Agua, y ciento mas que la Tierra: y el Fuego diez tanto mas que el Ayre: y mil vezes mas que la Tierra. (fol xxxv verso)

One section of Sacrobosco’s Sphere that most sixteenth-century commentators took issue with was his discussion of the five climactic zones. Sacrobosco had asserted, following ancient authorities, that the region around the equator, the “torrid zone,” was too hot to sustain life, and the regions around the North and South poles, the “frigid zones,” were too cold to sustain life. Only the “temperate zones” in between these extreme regions were capable of supporting life. In the sixteenth century, many of Sacrobosco’s readers and commentators asserted that the recent voyages of exploration conclusively refuted the notion that some regions of the globe were too hot or too cold for people to live in. Chaves actually defends Sacrobosco – and by extension ancient authorities – on the subject of the climactic zones. He asserts that the term “uninhabitable” should not be taken literally. Ancient writers were well aware, he writes, that regions of the globe that fell in the torrid or frigid zones had human inhabitants. They knew of “Arabia Felix” (Yemen), “Taberbana” (probably Sumatra), Ethiopia, Meroë, and the Troglodyte region (on the African coast of the Red Sea). Chaves concludes:

Wherefore it is clear that, as they had news that in such places, or zones, there were inhabited areas, they did not mean that they were literally uninhabitable. They only wanted to express that such regions and areas were not suitable to be inhabited. And so we say that a house is uninhabitable, not because it is not inhabited, but because it is not so sufficient or so good as another.

Por donde esta claro que como ellos tuviessen noticia que enlas tales plagas, ò zonas vuise terras abitadas, no avian de dezir que fuessen inhabitables, estando enla rigor del vocablo. solo quisieron sentir que las tales regiones y zonas no eran convenientes para ser habitadas. Y assi dezimos que una casa es inhabitable, no porque no se habite, sino porque no sea tan sufficiente ni tan buena para que se more como otra. (fol. liiii)

According to Chaves, the people in the torrid and frigid regions were wilder and more animal-like than the inhabitants of the temperate zone. People in the torrid region were exposed to excessive heat “which burns their bodies, and blackens them, and dries the humors, and bakes their faces, and weakens their limbs” (les quema sus cuerpos, y los ennegresce, y desecca los humores, y assa les los rostros, y enflaquece sus miembros). Their hair is “black and frizzy” (negros, y crespos) and their social customs are “wild and without temperance” (silvestres y sin temperamento). People in the frigid zones are very pale, with red hair and large soft bodies. They too are savage and uncivilized. Chaves claims, “There are in these lands or cold areas, men who eat human flesh, and drink blood: as there are also in the torrid zone” (Y hallanse enestas terras ò zonas frias, hombres que comen carne humana, y beven la sangre: segun que tambien se hallan enla torrida zona.). The torrid and frigid zones are full of “evil people, and devils, and beasts who are inimical to human nature” (malignos, y diablos: y crianse bestias que son empecientes a la naturaleza humana). By contrast, the inhabitants of the temperate zone are “better and healthier men” (los hombres mejor y mas sanos).

Chaves might have used his own translation of the Sphere as a textbook when he taught pilots at the House of Trade, but I have no direct evidence that he did this. Indeed, as the book was published seven years before he took up the Chair of Cosmography, it seems unlikely this was his original motivation for producing a translation. If anything, this edition seems to emphasize the theological and philosophical dimensions of astronomy and cosmology far more than its practical benefits. Even astrology gets relatively brief attention throughout the text.



Jerónimo de Chaves, Tractado de la sphera que compuso el doctor Ioannes de Sacrobusto con muchas additiones (Seuille: Juan de Leon, 1545).


Barrera-Osorio, Antonio. Experiencing Nature: The Spanish American Empire and the Early Scientific Revolution (University of Texas Press, 2006).

Gómez Martínez, Marta. 2013. “Claves didácticas en un manual de astronomía: De Sphaera Mundi de Sacrobosco.” Relaciones: Estudios De Historia Y Sociedad 34, no. 135: 39-58.

Lamb, Ursula. Cosmographers and Pilots of the Spanish Maritime Empire. Brookfield, Vermont: Ashgate, 1995, esp. VIII.

López Piñero, José María. Diccionario Histórico De La Ciencia Moderna En España. ed. Barcelona: Península, 1983, vol. I, pp. 180-181.

Martínez, Antonio Sánchez. 2010. “Los métodos pedagógicos de la Corona para disciplinar la experiencia de los navegantes en el siglo XVI.” Anuario De Estudios Americanos 67, no. 1: 133-156.

Portuondo, Maria. Secret Science: Spanish Cosmography and the New World (Chicago: University of Chicago Press, 2009).

Sandman, Alison Deborah. “Cosmographers vs. Pilots: Navigation, Cosmography, and the State in Early Modern Spain” (PhD dissertation, University of Wisconsin, Madison, 2001), esp. chapter 4.


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