The Literature of the Heavens and the Science of the Stars

PRINTING, PLANETARY THEORY, AND THE GENRES OF FORECAST

In the fifteenth century, a vast and complex literature described, explained, and invoked the motions of the heavens and their influences on the Earth. From the 1470s onward, the learning of the heavens, much of it inherited from the ancient and medieval worlds, began to acquire a new sort of accessibility as it was reproduced in the medium of print. This chapter describes the broad contours of that literature and its various classifications. It shows how those categories evolved, how it worked as a body of knowledge, and the peculiar forms that it took in the sixteenth century. This corpus of writings—rather than an exclusive and autonomous stream of planetary theory—constituted the foundational categories of the intellectual world in which Copernicus was educated at Krakow and Bologna in the 1490s and in which his work took form and was later evaluated.

Interest in astrological prognosticating had begun to catch on in the Latin West as far back as the twelfth century, with the arrival of sophisticated Arabic astrological writings. Among the most influential of such works was the Great Introduction to Astrology of Albumasar (Abu'Mashar), which emphasized the preeminent effects of great planetary conjunctions. Soon, a good many medieval practitioners were attracted by the prospect of using the heavens in medical prognosis as well as retrospective diagnosis. The popular "zodiac man," representations of which abounded by the fourteenth century, mapped signs of the zodiac onto the body parts that they ruled: it assisted surgeons in deciding when to bleed the patient and guided physicians in prescribing a diet that would counteract a specific disease. The Black Death (or bubonic plague) of 1347–51, which killed one-quarter to one-third of Europe's inhabitants, greatly accelerated a sense of loss of social control and, with it, augmented the special credibility of Albumasarian causal explanations grounded in the power of planetary conjunctions. In the last decade of the fifteenth century, another new and frightening disease entity appeared, accompanying the massive movement of French armies into Italy. It too killed, but first by attacking the genitals. Was this "French disease," as many non-Frenchmen called it, caused by a conjunction of Saturn and Jupiter on 25 November 1484? Was it, soon afterward, augmented by a "horrible" solar eclipse on 25 March 1485? Or did God act directly, without need of celestial influence, to punish men for their sins? Whatever the preferred explanation, "astrology had come to stay," as Olaf Pedersen has aptly observed, "and many scholars came to regard astronomy principally as a theoretical introduction to astrological practice."

It is difficult to generalize with confidence about the full range of astrological works that were composed before the era of print. The extant remains of the considerable library of Simon de Phares, astrologer to the French king Charles VIII, may be a useful indicator; it was principally a collection devoted to the destinies of individuals. Insofar as medical astrology concerned individual patients, that would partly account for such a focus. However, the arrival of syphilis with Charles's marauding armies spawned a genre of writing about the new plague that applied not just to individuals but to groups. Ptolemy had already classified prognostications into two kinds—those concerning "whole races, countries and cities" (general) and those relating to individuals (specific). Print technology made possible the first kind in a way that had not previously existed. Just over twenty years after Gutenberg published the first book in the West, an almanac for the year 1448, the urban or regional forecast became a standard part of the literature of the heavens and soon dwarfed all other types. Although these annual prognostications occasionally circulated in manuscript, by the 1470s they appeared regularly in print and gradually began to displace hand-produced predictions.

Annual astrological prognostications were part of a larger pattern. Overwhelmingly, the celestial productions that the early printers chose to put on their trade lists were short works intended for practical use: single-leaf wall calendars, almanacs, ephemerides (tables of daily planetary positions), lunar tables, and eclipse forecasts. Ernst zinner's bibliography of "astronomical literature" published in "Deutschland" over the period 1448–1630, comprising more than five thousand items, illustrates this contention by enabling a gross count of different sorts of writings produced by publishers in the domains of the Holy Roman Empire. One can only guess at bibliometric patterns for the rest of Europe, and it is impossible to determine absolute numbers of copies.

Gradually the emerging culture of print dressed up its products. It used a variety of new techniques to encode already existing literatures of heavenly representation, such as visually compelling title pages; epistolary dedications to a patron or general dedications to the general reader; and didactic woodcuts displaying spheres, circles, angles, and movable planetary discs, or volvelles. Regiomontanus, the earliest printer of celestial works, pioneered techniques of setting type for astronomical woodcuts, including those that he used to illustrate the models for Peurbach's New Theorics of the Planets. Print technology also had undeniable consequences for the conditions of...