Claudius Ptolemy’s astronomical treatise, written in about 150 CE was originally titled ‘Mathematike Syntaxis’ (‘Mathematical Arrangement’). When it was translated from the Greek into Arabic in the late eighth and early ninth centuries, it became known as the ‘Almagest’, from the Arabic: لْمَجِسْطِيّ, ‘al Megiste’ (‘The Greatest’) in Arabic. It was first translated from Arabic into Latin by Gerard of Cremona in the second half of the twelfth century, but it was not until the fifteenth century that manuscripts in both Greek and Latin began to circulate widely throughout Europe.

On 5 May 1460, Cardinal Bessarion (1403–1472), the papal legate to the Holy Roman Empire, arrived in Vienna on a diplomatic mission. There he met both Georg von Peurbach and Johannes Regiomontanus. Bessarion was a considerable collector of Greek manuscripts with a keen interest in the exact sciences. One of his projects was the creation of a new translation of the ‘Mathematike Syntaxis’ from the Greek to replace Gerard of Cremona’s version and improve upon the erroneous Greek translation by George of Trebizond in 1451. He also desired an abridgment of the ‘Mathematike Syntaxis’ to use as a textbook.

Although Peurbach was unfamiliar with Greek, according to Regiomontanus he knew the ‘Almagest’ almost by heart (‘quem ille quasi ad litteram memorie tenebat’) and so took on the task of preparing the abridgment titled as ‘Epytoma in Almagestum’.
 Further plans were made for Peurbach and Regiomontanus to accompany Bessarion to Italy and there work with him, using Bessarion’s Greek manuscripts as the basis of the new translation. Peurbach, however, had completed only the first six books of the abridgment when he died in 1461, not yet thirty-eight years old. On his deathbed, he made Regiomontanus promise to complete the work, which the latter did in Italy during the next year or two. This account is given by Regiomontanus in his preface to the ‘Epytoma in Almagestum’. The completed work was dedicated to Bessarion by Regiomontanus, probably in 1463, in a very careful and beautifully executed copy (now Venice, Biblioteca Marciana, lat. 328, fols, 1–117).

Regiomontanus had hoped to publish ‘Epytoma in Almagestum’ much earlier than 1496 at his own short-lived Nuremberg press (active 1473–1475), but his premature death at the age of 40 in 1476 delayed its appearance for more than twenty years. 

The ‘Almagest’ consists of thirteen sections, called books. These discuss a general cosmology of the universe, including: the spherical form of the Earth and the Heavens (Book I); problems associated with the daily motion attributed to the Heavens (Book II); The length of the year and the motion of the Sun (Book III); the motion of the Moon (Books IV and V); solar and lunar eclipses (Book VI); the motion of the fixed stars and precession of the equinoxes with a catalogue of 1,022 stars (Books VII and VIII); issues with creating models for the five naked-eye planets, and the motion of Mercury (Book IX); the motion of Venus and Mars (Book X); the motions of Jupiter and Saturn (Book XI); stations and retrograde motion (Book XII); and motion in latitude (i.e., the deviation of planets from the ecliptic) (Book XIII);

To create his star catalogue, Ptolemy states that he ‘observed as many stars as it was possible to perceive, even to the sixth magnitude’, during the reign of Antoninus Pius (138 CE). The layout of the star catalogue and its 1,022 stars is tabular with coordinates registered in two columns of elliptical longitudes and latitudes. Claudius Ptolemy’s choice of an elliptical rather than an equatorial coordinate system distinguishes him from all his predecessors and gave his catalogue much higher precision. ‘The Almagest’ star catalogue remains the oldest surviving exemplar with complete tables of coordinates and magnitudes from the classical era.

Ptolemy assigned the following order to the planetary spheres, beginning with the innermost: Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn, and the Sphere of fixed stars. Other classical writers suggested different sequences, but Ptolemy's authority was preferred by most medieval Islamic and European astronomers. Ptolemy repurposed his predecessors’ geometrical models and formulae to create predictions for the appearance of the planets in the sky. ‘The Almagest’ adopted Hipparchus's solar model, which consisted of a simple eccentric deferent. For the Moon, Ptolemy began with Hipparchus's epicycle-on-deferent, then added a further device called the equant to successfully create models for the other planets, where Hipparchus had failed.

Ptolemy wrote ‘The Almagest’ as a textbook of mathematical astronomy. It explained geometrical models of the planets based on combinations of circles, which could be used to predict the motions of celestial objects. In a later book, the ‘Planetary Hypotheses’, Ptolemy explained how to transform his geometrical models into three-dimensional spheres or partial spheres. In contrast to the mathematical ‘Almagest’, the ‘Planetary Hypotheses’ is sometimes described as a book of cosmology.

The ‘Epytoma in Almagestum’ (Epitome of the Almagest), is an epochal work by the leading astronomer of the fifteenth century, Johannes Regiomontanus. It constitutes, within the editor’s commentary, the first printed Latin translation from the Greek of the monumental astronomical compendium of Claudius Ptolemaeus of Alexandria known as ‘The Almagest’. The publication of the work directly inspired Nicolaus Copernicus to question the geocentric theory of the universe, which resulted in the publication of his ‘De Revolutionibus Orbium Coelestium’ (1543), the foundation of modern astronomy.

‘The Almagest’ of Ptolemy (90–180 AD) had been known since the late 1100s through a poor Arabic translation until Cardinal Bessarion charged the eminent Georgius Peurbach with the task of properly editing the text. Only the first four books were completed when Peurbach died in 1461 and the work was finished by his pupil Regiomontanus, whose xylographic portrait graces the interior. With its completion, classical Greek astronomy suddenly became accessible to Latinate Europe. 

This rare example of the first printed edition of Claudius Ptolemy's 'Almagest' forms an important cornerstone of the cross-cultural evolution of human knowledge. The title derives from the transliteration of the Arabic: اَلْمَجِسْطِيّ, ‘al Megiste’ (‘The Greatest’), and it was enormously influential to medieval Islamic scholars and later to Renaissance Europe. Ptolemy’s work discusses astronomy and was arguably his most influential book, alongside the '

' (on geography) and the 'Tetrabiblos' (on astrology). 

In his writings challenging the Ptolemaic system, Nicolaus Copernicus often referred to ‘The Almagest’ by Georg von Peurbach and Johannes Regiomontanus. This work did not just serve as foil to Copernicus’s new theories; it also contained proofs that were fundamental to his development of a heliocentric system. 

Title page

Frontispiece

Page with circular diagrams

Illuminated letter 'T'

Illuminated letters

Illuminated letter 'V'

Illuminated letter 'O'

Illuminated letter 'S'

Illuminated letter 'D'

Illuminated letter 'A

Illuminated letter 'L'

End page

An extremely rare example of Claudius Ptolemy’s ‘Almagest’, bound in a delicate contemporary Italian binding. The book was, at once, the foundation of both classical and modern astronomy: the first appearance in print of a Latin translation of the work from the original Greek which, when read by Nicolaus Copernicus, inspired the work which led to the publication of his own revolutionary ‘De Revolutionibus’ in 1542.

Original Italian binding comprising a 13th-century vellum leaf, from a manuscript of Justinian’s 'Digest', over paper boards, with ties, “an exactly contemporary Italian long–stitch binding sewn through a full primary cover of blue cartonnage with a secondary cover of medieval manuscript waste, with alum–tawed skin ties at head, tail, and fore–edges”, the use of the blue cartonnage “is less common – though used for the covers of some of the little long–stitch notebooks used by Leonardo da Vinci in the same decade (1490s)” (Professor Nicholas Pickwoad). 

Folio. Xylographic title-page, full-page woodcut of Claudius Ptolemy and Regiomontanus seated beneath an armillary sphere, within a fine white-on-black woodcut border, 279 woodcut diagrams (including repeats), 6-, 7-, and 14-line white-on-black floriated and historiated woodcut initials, woodcut printer’s device on colophon leaf, with some deckle edges.

An Epitome of Ptolemy's 'Almagest'

Epytoma in Almagestum Ptolemaei

Claudius Ptolemy; Johannes Regiomontanus or Johann Muller; Georg Peurbach 