Sacrobosco - Sphaera - 1610

A journey within the system of spheres and its arcana: the secret language of the firmament
Sacrobosco's work, the quintessential medieval astronomical manual, continued to be reprinted and commented upon in the seventeenth century as a compass for navigating the order of the heavens, the motions of the planets, and the geometries of the Aristotelian-Ptolemaic universe. The 1610 Cologne edition, published by Petrus Cholinus, offers a clear typographical layout with numerous woodcut illustrations explaining orbits, eclipses, celestial spheres, equinoxes, solstices, and cosmic phenomena, making visible what could only be imagined at the time. It is a work that crosses into modernity as cosmology is revolutionized: an ancient text that survives thanks to its pedagogical and symbolic power. The images of eccentric circles and solidified spheres do not merely depict a physical model but represent an entire vision of cosmic order, where astronomy, natural philosophy, and metaphysics converge.
Market value
The market for sixteenth-century editions of Sphaera varies significantly depending on the condition, the presence and integrity of the illustrations, the provenance, and the quality of the binding. Copies with ancient annotations related to astronomical content, complete apparatus, or with notable academic provenance can exceed 1,700–2,000 euros.

Physical description and condition
Contemporary binding in full stiff parchment, with traces of ties; boards slightly warped. Spine with raised bands, unlettered. Some browning, foxing, and stains. Tarlike traces. Astronomical woodcuts, geocentric models, eccentric orbits and epicycles, diagrams of celestial motion, figures on lunar and solar eclipses. Pages (2); 262. Copy with signs of use that retains its esoteric charm. In old books, with a multi-century history, some imperfections may be present, not always noted in the description.

Full title and author
Sphaera.
Cologne, at Petrus Cholinus, 1610.
Johannes de Sacrobosco.

Context and Significance
La Sphaera is one of the longest-standing texts in the history of science: it was created around 1230 as a compendium of Tolemaic astronomy and became, for over four centuries, the fundamental manual for schools and universities across Europe. Its success stems from its clarity of exposition, its concise structure, and its ability to make accessible a complex cosmology based on spheres, celestial motions, equinoxes, eclipses, and sky geometries.
The edition of Cholinus fits into the heart of the astronomical revolution: in 1610, Galileo published the Sidereus Nuncius, but the academic world continued to reprint Sacrobosco as the theoretical foundation. It is an edition that testifies to the coexistence of two paradigms — the old Aristotelian-Ptolemaic order and the new Copernican universe — and reveals how deep the cultural roots of traditional astronomy were. The woodcut figures in the volume are not simple illustrations but conceptual diagrams: tools of thought that organize the pre-modern cosmic vision.
In this sense, the book is not merely a technical compendium: it is a symbolic map of the universe, a mental cosmography in which mathematics, philosophy, and even elements of magical-naturalistic cosmology converge into a coherent system.

Biography of the Author
Johannes de Sacrobosco (c. 1195–1256) was a mathematician and astronomer, probably of English or Irish origin, active at the University of Paris. His Sphaera mundi experienced extraordinary dissemination from the Middle Ages to the early Seventeenth century, becoming the most influential astronomical textbook in Europe. His clarity in explaining the Ptolemaic system helped to entrench geocentric cosmology for centuries. Sacrobosco was also the author of the Computus ecclesiasticus, essential for calculating Easter.

Printing history and circulation
La Sphaera was one of the most reprinted books in European scientific history: over 200 editions from the 15th to the 17th century, often accompanied by illustrations and constantly updated commentaries.
The editions from Cologne, particularly widespread in the seventeenth century, responded to the strong demand from Jesuit colleges, Catholic schools, and private readers interested in elementary astronomy. The workshop of Petrus Cholinus, active during these decades, produced several editions of basic scientific texts, with great attention to the clarity of the illustrations.
La Sphaera continued to be used even when the Ptolemaic model was already outdated, thanks to its ability to present an ordered and readable cosmic system: a useful theoretical introduction even in environments where the new heliocentric models were studied.

BIBLIOGRAPHY AND REFERENCES
Collective catalogs (BNF, WorldCat, ICCU) for comparison of seventeenth-century variants.
Thorndike, Lynn, A History of Magic and Experimental Science.
Swerdlow, N. M., “The Derivation and First Draft of Copernicus’s Planetary Theory”.
Pedersen, Olaf, Early Physics and Astronomy: A Historical Introduction.
Dreyer, J. L. E., A History of Astronomy from Thales to Kepler.
Studies on the medieval and humanistic tradition of the Sphaera, catalogs of editions from the 16th–17th centuries, bibliographic repertoires on premodern astronomical education.