CLAVIUS, Christophorus (1537-1612). In sphaeram Ioannis de Sacro Bosco commentarius, Rome, 1581, large 8vo, woodcut diagrams and initials, tables, modern vellum with yapp edges. The work was first published in 1570.

CLAVIUS, Christophorus (1537-1612).  In sphaeram Ioannis de Sacro Bosco commentarius nunc iterum ab ipso auctore recognitus, & multis ac variis locis locupletatus. Rome: Ex Officina Dominici Basæ [On colophon:] Apud Franciscum Zanettum, 1581. Large 8vo (206 x 145mm). Large woodcut armillary sphere on title, numerous diagrams and initials, some historiated, tables, large woodcut printer's device at the end (lacks all before title [i.e. blanks], title quiet heavily spotted and with repair on verso, variable staining and spotting throughout). Modern old-style vellum with yapp edges, title in manuscript on spine, new endpapers. First published in 1570, this work by "the Euclid of the 16th-century" became a standard textbook on astronomy and went through several editions. It demonstrates the Jesuit author's continued avowal of a strict geocentric model of the universe, even some 27 years after the first publication of Copernicus's De revolutionibus in 1543. Despite this, when Galileo published the Sidereus nuncius in 1610, Clavius, after initial scepticism, came round to accepting many of its tenets, and these were incorporated into later editions of In sphaeram. Adams C2100; Houzeau & Lancaster I, 2678; cf. PMM 113 (citing Galileo's Sidereus nuncius): "[Galileo's] discoveries in the Sidereus nuncius did not prove that Copernicus was correct. Not even his later discoveries (of sunspots and the phases of Venus) did this; nor did any of Galileo's later polemical writings. But Galileo did prove that the Aristotelian-Ptolemaic world-view must be wrong. Even his clerical opponents (like the Jesuit astronomers Clavius and Scheiner) were soon compelled to admit it"; Sommervogel II, 1212.