The Geometrical Diagrams in Regiomontanus's Edition of his own Disputationes (c. 1475): Background, Production, and Diffusion

Despite its brevity, the career of the astronomer Johannes Regiomontanus (1436-76) intersected significantly with the new technique of printing with movable type. His first known accomplishment, as a thirteen-year-old university student at Leipzig, was the computation of a set of planetary tables vastly more impressive than Gutenberg's own so-called "astronomical calendar of 1448". By dint of his precocious astronomical knowledge, his facility with arithmetic, and his Sitzfleisch, Regiomontanus not only computed planetary positions at new and full moon (as in Gutenberg's almanac), but also offered daily planetary positions. Although Ernst Zinner believed that Regiomontanus 's 1448 computations were stimulated by the first known almanac printed with movable type, there is no evidence for such a link.1 Whether Regiomontanus first encountered the "black art" in Leipzig or Vienna, it made a deep impression on the young astronomer. Regiomontanus spent the 1450s studying, teaching, and doing astrological consulting in and near Vienna, and split the 1460s between Italy (the household of Cardinal Bessarion) and Hungary (the courts of Archbishop Janos Vitez and King Matthias Corvinus). He then set up in Nuremberg a printing shop dedicated primarily to works of astronomy and mathematics (147 1-75). These years proved to be all but the last of his short career. His death during a trip to Rome (1475-76) left behind a long list (printed, of course) of unfulfilled typographical plans. Among the nine editions he did produce were echoes of his earliest efforts, which he took to new heights. His own 30-year calendars in German and Latin editions (1474-1504) and his massive 896-page Ephemerides, with daily planetary positions for 1475-1506, remain impressive for both their contents and their evidence of his computational stamina.2These works, and the other editions Regiomontanus printed, deserve attention from the point of view of technical bibliography, and not simply because he was the first to print his own works.3 He incorporated in his productions the first solutions to a host of typographical problems: tabular data (hundreds of pages); pioneering printed geometrical diagrams, illustrations of eclipses and planetary models (some systematically coloured by hand under the supervision of the press); the first volvelles and sundials with built-in brass arms in a printed book. He was one of the early experimenters in printing decorative initials alongside his types, an issue I reserve for detailed treatment in a future publication. Regiomontanus 's emulation and adaptation of the elegant scribal practices in the fifteenth-century manuscripts shaped the way later printed astronomical books looked and left a lasting imprint on the typography of mathematical works.4 Well into the sixteenth century, German and Italian printers working in Venice in particular imitated his innovative results and disseminated copies of his illustrations in their own editions. Even the frescoes of Giorgione bear witness to the diffusion of these figures in the early sixteenth century, as we shall see.This paper explores in preliminary fashion only one facet of Regiomontanus's printing achievement, namely the context, layout, production, and (briefly) the diffusion of his Mercury diagrams in his own Disputationes contra deliramenta cremonensia. Written as an occasional piece in Rome (1464), this short dialogue came off the press about a decade later in Nuremberg (c. 1475). Soon thereafter, his death unexpectedly made it his last edition. The chief burden of this little book was a critique of the Theorica planetarum communis, the anonymous thirteenth-century university textbook sometimes attributed to Gerard of Cremona. After sketching the links of both Regiomontanus's critique and his layout to the manuscript tradition in Vienna, I illustrate his innovations as a printer by focusing on his diagrams of the Mercury models in particular. My concern here is not so much their geometrical content or their role in the argument (discussed in detail in a forthcoming monograph) as the material and typographical features of these figures. …