REGIOMONTANUS (MÜLLER, Johann) and PURBACH, George.

Epitoma in Almagestum Ptolemaei.

      - Venice, Johannes Hamman for Kaspar Grossch and Stephan Roemer, 31 August 1496. FIRST EDITION, first issue. Folio. ff. (cviii). [a10, b-n8,6, o6, p8] last blank, 48 lines and headline. Gothic letter, some Greek. 8 fine 14 line white on black woodcut historiated and floriated initials, numerous six line white on black initials, 279 woodcut marginal diagrams (including repeats), xylographic title, woodcut printer's device on verso of p7, full-page woodcut of Ptolemy and Regiomontanus in discussion below a large armillary sphere, within a fine white-on-black ornamental border. A few marginal annotations in an early hand, pencil acquisition note of S.S. Dunham 1931 from Hoepli sale Milan. Very occasional and minor light marginal mark. A fine, tall copy, crisp and clean (unwashed) in very fine impression, in early vellum, recased. First edition of the first appearance in print of Ptolemy's 'Almagest', an encyclopedia of astronomical knowledge which established astronomy as a mathematical discipline. It is the only incunable edition, preceding the first complete edition by 20 years; a full Latin translation appeared in 1515. Much of the text derives from Hipparchus, whose originals are now lost. It contains an elaborate theory of the planets, the discovery of the second inequality of the moon's motion, the determination of the distance of the moon, an exposition of spherical and plane trigonometry and an account of the construction and use of astronomical instruments. "The importance of this book lies in the fact that it enshrines, within the editor's commentary, the first appearance in print, in a Latin translation from the Greek, of the monumental compendium of Claudius Ptolemaeus of Alexandria known as the Almagest (an Arabic portmanteau word derived from the Greek for 'the great astronomer')". PMM. In 1460 Peurbach, professor of astronomy at the University of Vienna, was persuaded by Cardinal Bessarion, then papal legate to the Holy Roman Empire, to undertake a briefer and more comprehensible Latin condensation of Ptolemy's formidably complex Syntaxis. Peurbach based his epitome on a copy that he himself had transcribed of Gerard of Cremona's 12th-century translation. He died just after completing Book VI, and the remaining seven books were completed, using a more accurate manuscript, by his former student, friend and colleague Johannes Müller of Königsberg (Regiomontanus), who dedicated the final text to its patron Bessarion. In Regiomontanus's manuscript, preserved in the Institut de France, he did not address Bessarion as Patriarch of Constantinople (a title which is used in the printed edition), showing that the manuscript must have been completed before 28 April 1463. Regiomontanus determined to master the language of Ptolemy and he acquired remarkable fluency in Greek from his close association with Bessarion, which combined with his mathematical and astronomical knowledge meant that he was one of the few people in Europe with the required expertise to undertake such a task. The importance of the work in the history of science in Europe is demonstrated by the fact that Copernicus, whilst a student in Bologna, was struck by an error in Ptolemy's lunar theory (book V, proposition 22 in the Epitome), which lead him to overthrow the Ptolemaic system and lay the foundation of modern astronomy. "At the end of the fifteenth century, Ptolemy's achievement remained at the pinnacle of astronomical thought: and by providing easier access to Ptolemy's complex masterpiece, the Peurbach-Regiomontanus Epitome contributed to scientific research rather than to improved understanding of the past. Moreover, the Epitome was no mere compressed translation of the Syntaxis, to which it added later observations, revised computations, and critical reflections." (DSB 11:349). As usual without the bifolium containing a letter dated 15 August 1496 inserted in a few, later copies. Given most copies do not contain a letter dated only 15 days before the