Giordano Bruno's bold signature in his De revolutionibus, now in the Biblioteca Casanatense in Rome.
Visitors to Rome have no trouble seeing the magnificent Vatican art collection because the Vatican Gallery abuts the edge of Vatican City, and tourists can enter to view the paintings and sculptures without needing to enter the Vatican grounds themselves. The Vatican Library is another matter, located more deeply in the territory of the Holy See. There was then (and probably still is) a visa office with full Italian-style bureaucracy. And here was an occasion when a Harvard "dazzler" letter stood me in good stead. A senior colleague had alerted me that the office of the University Marshal would prepare an official-looking document with an enormous gold seal that could help budge recalcitrant bureaucrats. Armed with my dazzler letter, I apparently passed muster. In those days gentlemen were required to wear a coat and tie. Ladies could work in the library only in the morning. In the afternoon, with no women present, men were allowed to hang their jackets over the backs of the chairs. That was one of the rules. I was asked if I wanted to see books or manuscripts.
"Books. Here are the shelf marks," I said, handing over a list of call numbers that Jerzy Dobrzycki had given me.
"But this is a manuscript," the clerk responded, pointing to one of the shelf marks on the list, Ottoboniana 1902. Puzzled, I asked for permission to see both books and manuscripts.
The Ottoboniana collection is especially interesting for Copernican studies. After the death in 1632 of King Gustavus Adolphus of Sweden, who had waged the Thirty Years' War to save northern Europe for Protestantism, with his officers helping themselves to libraries and art collections along the way, his scepter and the war loot passed to his daughter, Christina. Among other things, the twenty-two-year-old Queen Christina had hired the famous French philosopher Rene Descartes as a private tutor. The fifty-three-year-old Descartes, who was used to lying abed meditating till eleven every morning, was shocked by a regime that required him to get up for philosophy tutorials at 5:00 A.M. Alas, this chilly routine caused his demise, and he died in Stockholm in 1650, less than a year after his arrival. Soon thereafter Christina decided to abdicate, pack up her treasures, journey to Rome, and take up the Catholic faith. When she died in 1689, Pope Alexander VIII (the former Cardinal Ottoboni) acquired her library, whence it became part of the Vatican Library.
Knowing this piece of history, Jerzy Dobrzycki had gone to Rome for a systematic survey of the Ottoboniani, hoping to discover some unknown Copernican materials that had been confiscated by the invading Swedes and subsequently transported by Christina to Rome. Jerzy noticed that Ottoboni's collection included a copy of De revolutionibus, which had been classified as a manuscript volume on account of the extensive annotations bound at the back. Remembering that Copernicus had received the complete book only on his deathbed, Jerzy knew it couldn't have come from Copernicus himself, so he marched on in his survey, except that he copied out the shelf mark for me. Without that, I might never have found this copy, since it wasn't recorded in the catalog of printed books.
Inside the reading room there was another rule: only three books per day. But the library had two first editions and two second editions in the catalog of printed books, plus a rare copy of Rheticus' Narratio prima, and several other books I hoped to look at as well as Ottoboniana 1902. Eventually, after I had got a special dispensation from the prefect to exceed the limit, the fetchers at the circulation desk looked daggers at me. "Young whippersnapper!" they probably thought. "Who does he think he is that he can actually read six books in one day?"
One of the examples of De revolutionibus in the Vatican's printed books collection turned out to be quite special: a presentation copy from Copernicus' printer to the polymath Achilles Permin Gasser (who came from the same hometown as Rheticus). On the title page Gasser had penned part of a Latin poem, not a great classic but interesting:
By his renowned new theses, Copernicus
Is believed to have put the finishing touches to this art
Which Erasmus Reinhold eagerly grasped,
As a Thesean cord, and paved a sure path to the stars,
And, striving to surpass the Alfonsine labors, Shows how great he was in the celestial art*
This De revolutionibus annotated by Gasser had been part of the library of Heidelberg University, generously "given" to Graf von Tilly, the brilliant Bavarian Catholic general in the Thirty Years' War, to become a major part of the foundation of the Vatican's library of printed books.†
But the real thriller for me in the library that day was Ottoboniana 1902, and it was my turn to be dazzled. On its title page was a familiar motto: "The axiom of astronomy: celestial motion is uniform and circular or composed of uniform and circular parts." Clearly, the book had some connection with Erasmus Reinhold's copy, the book in Edinburgh that had precipitated the entire census, and which had the same motto penned on its title page. The link was confirmed by several of the extensive notes in the book itself, which matched some of Reinhold's. But there were annotations graphing the technical details of the planetary mechanisms not found in Reinhold's copy, and at the end, a wonderful series of diagrams showing at first the Copernican Sun-centered circles for the planets but then switching to Earth-centered arrangements. The transition point was specifically dated: 13 February 1578. A final geocentric diagram was labeled "the spheres of revolution accommodated to an immovable Earth from the hypotheses of Copernicus." The label seemed an oxymoron, since to us the essence of Copernicus is heliocentrism. How could the diagram have been both Copernican and geocentric?
This was extraordinarily exciting but extremely puzzling. Whose book could it possibly have been? The final diagram smacked of the geoheliocentric scheme proposed by the great Danish astronomer Tycho Brahe, not quite his final system but a logical stepping stone. In 1588 Tycho had proposed a system with the Earth at rest, with the Moon and Sun circling the Earth, but with the Sun carrying all the other planets in a retinue around it. Tycho was undoubtedly the most productive astronomical observer the world had yet seen. Night after night he had measured positions of the stars and planets, using precision instruments of his own design in the decades before the invention of the telescope. Convinced both by the reality of what he was observing and by a commonsense conviction that the Earth itself was immobile, he had sought a cosmological solution that preserved the elegant connections of the Copernican arrangement together with a solidly fixed central Earth. Published in his De mundi aetherei recentioribusphaenomenis*his Tychonic system bore an uncanny resemblance to the diagram at the back of Ottoboniana 1902. The Vatican diagram showed the Earth at rest in the center, with the Moon and Sun circling the Earth, but only Mercury and Venus circling the Sun. The outer planets still rode on epicycles, although a simple geometric link would have had them circling the sun, essentially switching their epicycles with the Sun's own circle. While in Ottoboniana 1902 there seemed to be some sort of embryonic generic relationship to Tycho's system, the Danish observer was already accounted for; I hadn't yet seen his copy, but it was well known to be in the Clementinum Library in Prague. The only clue to the ownership of Ottoboniana 1902 was that an early librarian had written in Latin on the title page, "embellished with autograph notes from a distinguished man." Who was that distinguished man?
Among the possible candidates that Jerry Ravetz and I had mentioned three years earlier, one stood out: Christopher Clavius, the Jesuit astronomer who had organized the Gregorian calendar reform. He had originally come from Germany, where he just might have seen Reinhold's thoroughly annotated De revolutionibus. In the 1581 edition of his thick textbook, Commentary on the Sphere of Sacrobosco, he had conceded only that Copernicus simply showed that Ptolemy's arrangement of the circles was not the sole possibility. If Clavius had made the 1578 notes in Ottoboniana 1902, the timing would have been just right for him to have added the remarks about alternate arrangements of circles into the revised 1581 edition of his textbook.
Leaving the Biblioteca
Vaticana in a state of higher consciousness, I pondered my next move. The following day was already accounted for: A note at the hotel told me that Massimo Cimino, director of the Rome Observatory, would fetch me and show me the observatory's Museo Coper-nicano, which contained both a first- and second-edition Copernicus. I hoped he might also get me into the library of the Accademia dei Lincei, the famous scientific society with historical links back to Galileo's day, and which, like the observatory's collection, held both editions. Cimino arranged it perfectly, and I saw all four books the same day. One was censored according to the instructions issued by the Inquisition in 1620 (with the replacement text in a very unsteady hand); another had the same places marked but was not actually censored. And another copy had minor notes written in London in 1605, a neat demonstration of the slow reshuffling of books over time.
Cimino was helpful in another important way: He put me in touch with Father D. J. K. O'Connell, S.J., the retired director of the Vatican Observatory. I told Father O'Connell what I had found, and asked him if he could help me obtain a sample of Clavius' handwriting. He replied that the Jesuit archive was downstairs from his apartment, and that he was sure he could find something. Our paths converged in the Vatican Library reading room the next morning. Father O'Connell had in hand Xeroxes of two Clavius letters neatly bracketing the date of the annotations. We were quite excited by the prospect of what the comparison might show. Placing the letters alongside Ottoboniana 1902, we looked carefully both at individual characters and at the "ductus," the general flow of the hand. It took only five minutes to be sure that Ottoboniana 1902 had not been annotated by Christopher Clavius.
I left Rome in an agitated state, turning over in my mind possible can-
Title page of the "Tycho Brahe" copy of Copernicus' book in the Clementinum in Prague.
didates, but I was stuck. The blocked-currency PL480 air tickets allowed a certain amount of creative scheduling, so I backtracked to Paris for one of the many Copernicus conferences scheduled in that quinquecentennial year. I vaguely recall chairing a session—not an easy task because several of the papers were in French and my aural French was pretty primitive. But I clearly remember my surprise at meeting one of the Czech scholars, Zdenek Horsky. Normally, he had a problem getting out from behind the iron curtain, but he had ghostwritten a Copernican lecture for the president of the Czech Academy, and the trip to Paris was his reward. Horsky had brought me a gift: a facsimile of the Prague De revolutionibus with the Tycho Brahe annotations. When I looked at the handwriting, I think my heart must have skipped a beat, for it looked suspiciously reminiscent of the hand I had just been poring over in Rome.
As soon as I got back to my Paris hotel, I checked my notes from Rome. There were too many coincidences to be accidental. Had Tycho annotated a second copy, and had I found a crucial intermediate stage in his thinking? I contacted PanAm, rebooked my flights, left Paris a day early, and headed back to Rome.
Father O'Connell accompanied me to the Vatican Library, both to smooth my way and to share the comparison between the Prague facsimile and Ottoboniana 1902. This time it took only five minutes to be thoroughly convinced that the hands matched, that Tycho had clearly annotated a second copy. The next step was to get photographs of key manuscript pages. Normally, this process could take from six weeks to six months, but Father O'Connell's presence was magic. He arranged for them to be completed in a few hours.
While we waited, Father O'Connell suggested that we go next door to the Vatican Archives to see the papers from Galileo's trial. That was an intriguing prospect, for the archival record contained not only the transcript of the infamous 1633 heresy trial but various ancillary pieces of evidence, including the famous "false injunction" supposedly issued in 1616 requiring Galileo neither to hold nor teach the Copernican system. The Galileo scholar Giorgio de Santillana had argued in his book, The Crime of Galileo, that the document was a forgery designed to frame Galileo. For many years I felt that the injunction was probably a genuine document that had been prepared but never notarized because it had never actually been served while Galileo was being interviewed by Cardinal Robert Bellarmine, the leading Catholic theologian who had been instructed to warn Galileo about the dangers of holding the Copernican view. But the most modern scholarship today indicates that notarization was not required, and the injunction was quite probably actually served. In that scenario Galileo conveniently forgot about it since he had also received a letter from Cardinal Bellarmine explaining what had happened and giving a more liberal reading. That letter, introduced as evidence in the trial, is also in the Vatican file.
Alas, the archives were closed for lunch, so Father O'Connell took me above the archives to the Tower of Winds, which not many visitors see because the stairway is too narrow for traffic to go both ways. "When Queen Christina turned up at the Vatican, the very timid Pope Alexander VII installed her as far away from his own quarters as possible," O'Connell explained as we ascended the stairs. "So he put her here, underneath the old observatory. It's a very unusual observatory because it was used just with a small orifice for sunlight and a brass meridian line on the floor. That way Clavius could show Pope Gregory XIII that the Julian calendar was ten days out of synchronization with the seasons.* The walls themselves have frescoes representing the winds, and that's why it's called the Tower of the Winds."
Once we were in the frescoed room itself, Father O'Connell pointed out that the allegory of the south wind was represented by the storm on the Sea of Galilee (from the account in all the synoptic Gospels), with the opening for the beam of sunlight in the mouth of Auster, the south wind himself. O'Connell went on to say that there had long been a tradition of painting over some potentially offensive detail after Christina arrived. When restorations of the frescoes were undertaken, the overpainting came to light: a scriptural motto under the north wind paraphrased from Jeremiah, Ab Aquilone pandetur omne malum (All bad things come from the north).
The planetary system, "accommodated to the immobility of the Earth from the hypotheses of Copernicus,"from Ottoboniana 1902 in the Vatican Library.
Tycho Brake's geoheliocentric system fromhis De mundiae ianeetrhe i recentioribus phaenomenis (Vraniborg, 1588)
Presently the photographs were ready; I thanked O'Connell heartily for his intervention, and carried on with the PL480 journey to Egypt. My mind was aswirl with the unexpected serendipity of my visit to the Vatican Library. When I had started my census, my goal had been to find something new about Copernicus with which to celebrate the Quinquecentennial, and here it was in spades.
BACK IN THE United States, I began to examine how the new discovery fit in with what we knew about Tycho Brahe. The Danish astronomer had published in 1588 his well-developed Tychonic system, with its fixed central Earth and with the Sun carrying the retinue of planets around it. Included was his claim that he had invented this cosmology five years earlier, that is, in 1583. But the diagrams in the Vatican De revolutionibus were dated 1578. However, they didn't show the completed system, and they were wrong in a crucial way. The final geocentric diagram in Ottoboniana 1902 placed the epicycles for Mars, Jupiter, and Saturn so they could glide perfectly past each other without bumping. It was as if they were made of crystalline quintessence—the heavenly "fifth element" of Aristotle— solidified and polished over the passing years of the medieval period. Unfortunately for the elegance of this arrangement, the reality of the planetary spacings required that the epicycle of Mars overlap with the sphere of the Sun. There was no question about Mars colliding with the Sun— the actual motions prevented that. But it looked unaesthetic, if not downright dangerous.
To Caspar Peucer, Erasmus Reinhold's successor as the astronomy professor in Wittenberg, Tycho wrote a revealing letter about the genesis of his system: "I was still steeped in the opinion, approved and long-accepted by almost all, that the heavens were composed of certain solid orbs that carried round the planets, and . . . I could not bring myself to allow this ridiculous interpenetrati
on of the orbs; thus it happened that for some time this, my own discovery, was suspect to me." Finally, he realized that crystal spheres are just a figment of the imagination and not required by the Bible. Freed from the limitations of crystalline spheres, he could allow the intersection of Mars's circle with the Sun's, so that's how he depicted the Tychonic system in his 1588 publication. And Ottoboniana 1902 revealed the trail of discovery, moving step by step from a heliocentric back to a quasi-geocentric arrangement. Furthermore, because of the underlying layer of Reinholdian annotations in the book, there was a clear connection between Tycho and the Wittenberg school. "This is a tremendous scoop," I had written to Miriam from the Rome airport. "It changes several things in the accepted Tycho biography [about how and when Tycho conceived of his Tychonic system] and it dramatically confirms my hypothesis that there was an intellectual link to Tycho via Erasmus Reinhold."
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