Though he was a close colleague of Reinhold, who referred to him as "our Joachim," it is not at all clear that they were good friends. Besides being immensely interested in astrology (concerning which Reinhold was rather indifferent), Rheticus became closely affiliated with a group of raucous and iconoclastic young poets. One of them scandalized the community with a vulgar lampoon of the university leaders, including a veiled insinuation that Reinhold's wife was unfaithful. The young man was sent packing, and most of the rest of the group found Wittenberg too uncomfortable for their continued presence. Even Rheticus decided it was time to take a trip, and armed with letters of introduction from Melanchthon, in 1538 he headed south to Nuremberg.
There he met the resident scholar, Johann Schoner, who busied himself with astrology, paper instruments,* and publishing the archive of important astronomical manuscripts left over from the previous century, when Johannes Regiomontanus, the most important astronomer of the 1400s, had lived there. Presumably, Rheticus found out from Schoner† about the new cosmology under development in that "far corner of the Earth" (as Copernicus himself described the northernmost diocese in Poland where he lived and worked). No doubt Schoner told him that the Polish astronomer, who worked as canon at the cathedral in Frauenburg,‡ had some incredible notions about fixing the Sun in the center of a planetary system, and throwing the seemingly solid, immobile Earth into motion. How in the world Schoner knew about Copernicus is anyone's guess. Some have assumed that since by 1514 Copernicus had sent out at least one known copy of his preliminary prospectus for his heliocentric system, the so-called Commentariolus, Schoner probably saw a copy. Or Schoner could have heard the news through the astronomical grapevine that demonstrably connected sixteenth-century astronomers. Witness the case of Reiner Gemma Frisius, a Dutch doctor and mathematician. As early as 1531 Gemma found out about Copernicus from a well-born Pole, Johannes Dantiscus, who had spent some time in the Low Countries and who had then served as Gemma's patron. So somehow the news had got around.
Life's exigencies had prepared Rheticus to be a rebel, and the heliocentric cosmology, so contrary to the deeply rooted beliefs of the day, must have inflamed his imagination. Psychologically wounded by the execution of his father, he was ready to thumb his nose at a conservative society scarcely prepared to entertain such a radical cosmology. Since there were apparently no details to read in Nuremberg about these stimulating novelties, Rheticus resolved to go to the source to find out precisely what Copernicus was proposing. He may well have received encouragement from both Schoner and the Nuremberg printer Johannes Petreius, who had an interest in seeing Copernicus' work published. Thus in 1539 Rheticus set out on the long journey to the shores of the Baltic in northernmost Poland. While there he decided that making a detailed map of that region would be a good idea, so it was fortunate that the young student he had recruited to go with him, Heinrich Zell from Cologne, had some experience in cartography. By what route they traveled, and by what means, is lost in the fog of history.* Did they walk? Or go on horseback? Or on a wagon? Since Rheticus on his journey to Frauenburg took along three handsomely bound large volumes for Copernicus, and probably some of his own books as well as clothes, he presumably had some form of transport. Quite possibly he used the sixteenth-century equivalent of a rental car, buying a horse in Germany and selling it after he arrived in Poland.
Rheticus must have intended a relatively short visit to Frauenburg, little imagining that his sojourn would stretch not just for a few weeks but for several years. Copernicus had had no formal connections with academia since graduate school in Bologna and Padua. He had neither students nor colleagues who could understand the technicalities of what he was doing. Hence the arrival at the Frauenburg cathedral of a young Wittenberg mathematician would no doubt have provided a unique and even exciting opportunity for the aging Copernicus. The Polish astronomer welcomed his visitor, eager to explain the advantages of his new cosmology.
Map of the portion of Europe relevant to Copernicus' life and times.
In retrospect it seems quite remarkable that the sixty-six-year-old Catholic canon at the Frauenburg cathedral—for that was Copernicus' tenured position, which gave him time and support for his astronomical studies—could take on as a long-term guest a twenty-five-year-old teacher from the centrum of Lutheranism. But in those days, before the Catholic conservatives at the Council of Trent had finally hardened the ecclesiastical lines, the Protestant struggle was still viewed as an intra-family quarrel.
For years Copernicus had been writing a treatise on his Sun-centered cosmology, as already promised long before in his Commentariolus, and by then he had a thick manuscript. But he had never had a disciple, someone to whom he could introduce the intricacies of his astronomy. So the two of them began to discuss his hypotheses, as they were called then, really a term closer in meaning to our modern word devices. Copernicus must have told Rheticus about both levels of his hypotheses—the big one being his cosmological arrangement that put the Sun near the middle of a system of planets (including the Earth) wheeling around it, and the secondary, more technical, batch of hypotheses that accounted for the details of planetary motion. As the two men sat together discussing the details of the heliocentric astronomy, the young Wittenberger became increasingly convinced that the world needed to learn what Copernicus had wrought.
Rheticus must have realized that there was no publisher in Poland who could take on a work so extensive and complex. It required a printer with an international outreach to make the publication financially viable. Even Wittenberg, with its busy textbook publishers, was hardly the place for such an enterprise. Maybe this is why Rheticus brought along the three bound volumes as a gift for Copernicus. Three of the five titles included therein had been printed by Petreius.* They gave visible evidence that the Nuremberg printer could handle Copernicus' magnum opus. Whose idea was this? Maybe Johann Schoner in Nuremberg had suggested that such a display could persuade Copernicus to send his manuscript back to Germany, or it might have been Petreius himself. Schoner was well connected with the Petreius shop, dusting off old manuscripts from the Nuremberg archives or producing new works of his own and sending one to press every year or so.
But Copernicus was reluctant to release his book to a printer. Scholars have deduced that he wanted time to incorporate the trigonometric methods of Regiomontanus's Triangles, one of the gift books from Rheticus, into the mathematical section of his treatise. Rheticus had brought along from Schoner some observations of Mercury, which Copernicus needed to upgrade the section on Mercury. And in making changes to some of the parameters in the planetary theory, he had not had time to bring the tables into full agreement with the revised numbers.† The book was still filled with inconsistencies not as yet ironed out. And Copernicus feared it would just be an object of scorn and derision, or would simply become the book nobody read.‡
To be persuasive, Rheticus needed a further strategy. He asked, and gained permission, to publish an introduction to Copernicus' astronomy. The booklet of seventy pages was printed in the spring of 1540 in nearby Gdansk. In the Narratio prima, or "First Report," Rheticus did not shock his readers at the outset with the heliocentric cosmology. He obliged them to work through a number of pages discussing, for example, complex details of "the motion of the Sun" before springing the big surprise: "These phenomena can be explained, as my teacher shows, by a regular motion of the spherical Earth, that is, by having the Sun occupy the center of the universe while the Earth, rather than the Sun, revolves on a great circle." Rheticus then rehearsed the reasons he had found the heliocentric arrangement compelling. He summed up his arguments by declaring, "All these phenomena appear to be linked most nobly together, as by a golden chain; and each of the planets, by its position and order and every inequality of its motion, bears witness that the Earth moves and that we who dwell upon the globe of the Earth, instead of accepting its changes of position, believe that the planets wander in all sorts of motions of their own." He even added an e
ncomium to Prussia, perhaps yet another ploy to soften Copernicus' reluctance, or possibly an attempt to secure the patronage of Duke Albrecht of Prussia.
The Narratio prima was received with such interest that a reprint appeared in Basel the following year; unlike the original printing, it actually displayed Rheticus' name on the title page. Still Copernicus hesitated, and Rheticus lingered. At last, after twenty-eight months in Poland,* Rheticus was entrusted with a copy of Copernicus' manuscript destined for the Petreius press in Nuremberg, and Rheticus undertook the tedious journey home to Saxony.
Having returned to Wittenberg in 1541 with the manuscript in hand, the long overdue Joachim was appointed a full professor, a signal recognition because then there were only four professors (including Reinhold) in the arts faculty. Because the curriculum was still influenced by the medieval quadrivium† —arithmetic, geometry, astronomy, and music theory—it made sense to have two of the professorships in mathematics. Reinhold had become professor of upper mathematics, and thus the astronomy teaching devolved on him. Rheticus became the professor of lower mathematics, that is, arithmetic, geometry, and trigonometry. He arranged for a local press to print the trigonometric part of Derevolutionibus under the title De lateribus et angulis triangulorum (On the Sides and Angles of Triangles), an up-to-date mathematics text since it included what was only the second published table of sines. Its title page clearly designated Copernicus as the author, even though Rheticus himself had greatly expanded the tables.
The title page of Rheticus' Narratio prima (Gdansk, 1540), the firstprinted announcement of Copernicus' heliocentric cosmology.
In addition to his teaching, Rheticus became dean of the arts faculty for the winter semester of 1541-42. Apparently the appointment was more of a bureaucratic chore than an honor, and faculty members rarely served two consecutive terms. Yet even before he had left Frauenburg, he had asked Duke Albrecht in Prussia (an important patron) to petition the elector of Saxony and the University of Wittenberg for another leave of absence, this time to take Copernicus' manuscript to Petreius' shop in Nuremberg and to see it through the press.
Meanwhile, Erasmus Reinhold, the senior astronomy professor who had stayed home, had edited a new, annotated edition of a traditional advanced astronomy textbook entitled The New Theory of the Planets, and Melanchthon, who was the quintessential preface writer, added an erudite section quoting Xenophon, Homer, Virgil, and Plato. But the most interesting front matter came from Reinhold himself, who, in his own preface, mentioned that he knew of "a modern astronomer who is exceptionally skillful, who has raised a lively expectancy in everybody; one hopes that he will restore astronomy." In case there was any doubt, in the second edition some years later Reinhold made the allusion to Copernicus specific.
Reinhold's hint and Rheticus' Narratio prima of 1540 had alerted the community of astronomers and astrologers that something unusual could be expected. Thus the greatest astronomy book of the sixteenth century, indeed, one of the epoch-making science books of all time, came with at least a modicum of warning. Finally, in the spring of 1543, it was ready at Petreius' press in Nuremberg. Its title page read like an optometrist's chart:
NICOLAUS CO
PERNICUS OF TORUN
ABOUT THE REVOLUTIONS OF
the Heavenly Spheres in Six Books
The first 5 percent dealt with the new Sun-centered cosmology, so "pleasing to the mind." The other 95 percent was deadly technical. It included a handbook of plane and spherical astronomy, a lengthy star catalog only slightly updated from the one in Ptolemy's Almagest (the "bible" of geocentric astronomy, composed around A.D. 150), detailed instructions for going from a sparse collection of observations to the parameters of the planetary orbits, and tables for the prediction of planetary positions. As the publisher's blurb, planted squarely in the middle of the title page read, "You have in this recent work, studious reader, the motion of both the fixed stars and the planets restored from ancient as well as recent observations, and outfitted with wonderful new and admirable hypotheses. You also have most expeditious tables from which you can easily compute the positions of the planets for any time. Therefore buy, read, profit." It was surely a text to be studied, but scarcely to be read straight through.
DID ANYBODY read it? This was the question that the historian of science Jerry Ravetz and I asked ourselves one Saturday evening in October 1970. We had rendezvoused in York, the cathedral town in England's largest county; I was en route to Scotland with my family, and he had come over from nearby Leeds, where he taught at the university. Ravetz and I were both friends of Copernicus because we were friends of Poland—he perhaps because he was a socialist who had retreated to England during the McCarthy era, and I felt connected to Poland because of my formative visit with the UNRRA horses twenty-five years earlier. Jerry had spent some time in Poland, where he had produced a provocative monograph entitled Astronomy and Cosmology in the Achievement of Nicolaus Copernicus. When the International Union for the History and Philosophy of Science appointed a committee to plan for the forthcoming Copernican Quinquecentennial in 1973—the five hundredth anniversary of Copernicus' birth—he was a natural choice for the committee; eventually, he became its secretary, steering the committee with consummate sensitivity around issues that still aroused passions, such as whether Copernicus was Polish or German. As a historian of astronomy, I, too, had become a member of the committee, so it was appropriate that we would get together during my family's trip north from Cambridge, where I was spending a sabbatical semester.
With the celebrations coming up in just under three years, our conversation naturally turned to Copernicus and De revolutionibus. It was such a formidably technical book, we reasoned, that few readers could really comprehend it much beyond the opening cosmological chapters. We remembered Arthur Koestler's claim that it was the book nobody read, and, thinking about various modern "great books" programs and its inclusion in the University of Chicago's encyclopedic Great Books of the Western World series, we concluded there must be far more twentieth-century readers than existed in its first decades. We even ticked off the potential sixteenth-century readers who might have made it to the end.
Rheticus and Reinhold headed our list. Andreas Osiander, the Nuremberg theologian and clergyman who finished the proofreading at the press, was necessarily a reader. Then we added Johannes Kepler, the brilliant German astronomer who in 1596 wrote the first unabashedly heliocentric treatise after De revolutionibus itself, and Michael Maestlin, his teacher at the University of Tubingen. Tycho Brahe, the great sixteenth-century Danish observer and builder of instruments, was another obvious choice.
We paused at the name Galileo Galilei. A physicist, he had little taste for the details of celestial mechanics; we figured he might have owned the book, but that it was unlikely he would have read it to the end. (What I was eventually to learn pretty much verified this judgment.)
Another astronomer working in Italy did make the short list, however: Christopher Clavius, the astronomer behind the Gregorian calendar reform, who had specifically mentioned Copernicus in 1581 in the third edition of his introductory astronomy textbook.*
Then we added the first Copernican in England, Thomas Digges, a man who once lived in the same block as William Shakespeare and whose library might have been of use to the playwright when he was researching background material for Hamlet. Since Digges had translated part of Copernicus' cosmology into English, he would surely have been a reader. John Dee, an eccentric Elizabethan wizard who owned the largest private library in England, must surely have at least owned the book, even if he didn't read it all.
But with those nine likely readers we bogged down, and our conversation drifted off to other topics such as the glories of the York cathedral. Then we bid each other farewell, as early the next day my family was headed toward Edinburgh.
In Scotland serendipity took its course. The Royal Observatory in Edinburgh holds a fabulous collection of rare astronomy books formed by the Earl of Crawford
late in the nineteenth century. For years these precious books had been mixed on the open shelves with the ordinary astronomy treatises, but at some point before I arrived they had been collected for safekeeping in a couple of enormous steel cupboards. Among these treasures I stumbled upon a first edition of Copernicus' De revolutionibus that was thoroughly annotated from beginning to end.
Such a discovery would probably have meant little to me except for that conversation just two nights earlier about how few readers we thought the book had had in its first years. If it was read so rarely, why was the very next copy I chanced upon so full of evidence of a most perceptive reader, who had marked innumerable errors and who had worked his way through to the very end, even past the obscure material on planetary latitudes that brought up the rear of the four-hundred-page volume?
The Royal Observatory, Edinburgh, the magnificent edifice resulting from the gift to Scotland in 1888 of Lord Crawford's astronomical instruments and library.
Furthermore, there was a fascinating motto penned across the title page (in Latin): "The axiom of astronomy: Celestial motions are circular and uniform or composed of circular and uniform parts" (plate 4b). I would have expected something like, "This crazy book fixes the Sun and throws the Earth into dizzying motion." But no such thing. Here was a reader who ignored the Big Hypothesis, but who was enthusiastic about the secondary ones. The rich annotations verified that interest—hardly anything in the cosmological chapters, but a dense thicket of marginal comments whenever Copernicus grappled with his little epicyclets that allowed him to eliminate what he believed to be one of Ptolemy's most obnoxious devices.*
The Book Nobody Read Page 3