Tycho and Kepler

by Kitty Ferguson

  Eventually, that was what they did. Though all over Denmark and Sweden castles and stately homes older than Uraniborg are still inhabited or lovingly preserved, nothing remains of Tycho’s. There is no record of a protest or any regrets when the cornerstone of his paper mill was found on Hven and removed to Knutstorp in 1824. It was donated then to the historical museum in Lund, but when the museum showed little enthusiasm about displaying it, it was trundled back to Knutstorp.fn2

  Tycho’s name remained anathema on Hven for generations. Not until the late twentieth century did attitudes on the island change and the legend of the evil lord who had built his detestable palace on the common land finally fade. Conservators of the site of Uraniborg planted a hedge to show its footprint, restored part of the outer wall and a quarter of the gardens, and made Stjerneborg a well-marked archaeological site. They built a small museum and are currently also trying to repair Tycho’s reputation, for the image of him as a half-mad, fire-breathing tyrant had spread into the history books. Revisionist descriptions of Tycho give him much more sympathetic treatment than he has received in the past. In the restored garden at Uraniborg, a splendid statue of him, robed, instrument in hand, gazes with powerful intensity at the heavens.

  The statue of Tycho Brahe that stands in the restored portion of the garden at the Uraniborg site on Hven.

  In December 1597 another Mars opposition brought Mars particularly close to Earth. “I wish he had been there,”12 Kepler would write much later, “because this opposition was a marvelous opportunity, not often recurring within a man’s lifetime, for finding Mars’s parallax.” The parallax of Mars would not be a weapon in the winning of the Copernican revolution. Tycho’s Mars observations, however, would be.

  fn1 Science historian Bruce Stephenson has quipped that “most of the larger problems2 that concerned Kepler throughout his career were raised in this book—raised, indeed, in its title!”

  fn2 The paper-mill cornerstone stands today in a place of honor just outside the door of Knutstorps Borg, its inscription still legible.

  14

  CONVERGING PATHS

  June 1597–November 1598

  TYCHO HAD RESIGNED himself to getting little work done during the move into exile, but traveling the alternately dusty and muddy roads did give him time to think about the future. Though he may have suspected that he would never go back, Tycho had not given up hope. He was not the first among his powerful family to be driven out of Denmark, nor would he, if he could manage it, be the first to return and regain former status. His foster uncle Peder Oxe and his brother Knud had managed no less.

  Tycho and his entourage settled into lodgings in Rostock in mid-June 1597, and the busy academic city was a tonic to his bruised ego. He had lived here for a while as a student and left missing most of his nose. There were still many Danes and good friends at the university, and they received Tycho warmly, treating him as one who came in triumph and with great honor, not in disgrace. His prodigious intellectual and technical accomplishments and the splendors of Uraniborg were legendary here. In Rostock Tycho and his family could enter St. Mary’s Church and receive Holy Eucharist together, something they had not been able to do in Denmark for eighteen years.

  Tycho began to put into motion the plans he had made during the journey. He had decided on several points of attack. The campaign to restore his honor and position in Denmark would begin immediately. It would include a direct appeal to King Christian1, with pressure brought to bear simultaneously from within Denmark (from Tycho’s still powerful relatives) and from influential people abroad. At the same time, he would settle his family, entourage, and equipment in a semipermanent location and resume his astronomy and the publication of his books. The quicker he could proceed with that, the more secure the future would be for them all, whether in Denmark or somewhere else. The third part of his plan was to exploit his network to secure a new patron among the royalty of Europe—someone else with fiefdoms and islands to bestow.

  Tycho drafted his appeal to King Christian, explaining why he had moved abroad without taking leave of the king, and reminding Christian of the promises made by his father Frederick, the Regency Council, and the Rigsraad. Rather than abide by those promises, Christian had cut off Tycho’s income. Tycho closed his letter by insisting that he would rather serve Christian than any other master but would seek a patron elsewhere if such service could not be rendered on “reasonable terms, and without damage to me.”

  Tycho had never been an obsequious courtier, but he had known when and how to appear deferential and how to flatter kings. Yet his appeal to Christian had the tone of a letter between equals who had the right to scold each other about unfulfilled promises, and it was certain to bring a negative response. Either Tycho wanted Christian to turn him down, or his pride and anger got the better of his good sense and political savvy.

  Perhaps Tycho was more resigned to leaving Denmark than he willingly admitted at the time. Uraniborg had become an enormous administrative burden. The research for which he had had such high hopes and designed his finest instruments—the search for Mars’s parallax—had ended in disappointment. Ahead were new challenges, and in Rostock he was filled with fresh energy and a renewed sense of his own worth. He could not in good conscience fail to make an appeal to Christian and apply what pressure he could on the king. However, he also used that appeal to remind Christian, and himself, that the king was not dealing with a groveling underling but with a proud man of enormous intellectual and social stature, who was willing to return only on his own terms. In Tycho’s domain—in the intellectual world, in astronomy—he clearly felt he ruled as surely by divine right as Christian ruled Denmark. With similar impatient, well-warranted, but ill-advised arrogance, Galileo would later incur the wrath of Pope Urban VIII. Tycho had at least been astute enough to remove himself and most of his worldly and scholarly treasure out of Christian’s reach.

  While waiting for Christian’s reply, Tycho began putting to use the European network he had cultivated for years. Duke Ulrich2 of Mecklenburg, King Christian’s grandfather no less, agreed to intercede with the king. His intervention may have done more harm than good, for he praised Tycho as a man whose equal it would be difficult to find and who was famous in many lands. Christian, wishing for a subservient, compliant Tycho, surely did not take well to this reminder. Tycho sealed his friendship with Duke Ulrich by lending the guardians of the duke’s two nephews ten thousand dalers—which also did not escape Christian’s notice. Tycho had cried poverty in his letter of appeal.

  In early September there had been no reply from Christian, and Tycho sent out a feeler in the campaign to find a new patron. He still thought in terms of islands, and the first letter went to Lord Chancellor Erik Sparre3 in Poland, asking about the possibility of obtaining an island in the Baltic from King Sigismund. For political reasons having nothing to do with Tycho, that suggestion came to naught.

  Also in early September, Tycho and his entourage left Rostock and took to the roads again. Tycho had decided to seek the hospitality and counsel of Viceroy Heinrich Rantzau of Schleswig-Holstein. Learning that the viceroy was not at home at his seat at Segebert Fortress, they traveled on to find him in Bramstedt.

  Rantzau was a prodigious and highly respected scholar, older, far richer, and more powerful than Tycho, and equally famous. He and Tycho had much in common. Rantzau had built many palaces, as richly adorned as Uraniborg with Latin epigrams, pavilions, and pyramids. Now in his seventies, he was still an astute politician. The two men proceeded to pool their knowledge and experience of the politics of royal patronage. Though Rantzau lived like a prince, he was only a viceroy and not a suitable patron for Tycho. However, he was in a position to lend Tycho a castle where he and his household could live until the moment came to return to Denmark or move elsewhere. Rantzau had plenty of castles. Tycho chose Wandsburg, on the outskirts of Hamburg.

  In late September Tycho’s coach, drawn by six horses4 and followed by the long train of slow
er conveyances, rattled over the drawbridge into the courtyards of this massive Renaissance palace. It was a splendid dwelling, worthy of a man of Tycho’s stature, where he could maintain the princely image he thought necessary for regaining the favor of King Christian or winning a new patron. It was also near the city, where there were engravers and printers for the publications Tycho was planning, and it had a tower with a clear view of the skies, roomy enough to set up instruments.

  In mid-October a courier from the Danish court picked his way among servants unpacking instruments, printing press, furniture, and personal belongings to hand a letter to Tycho’s secretary, who broke the seal and read it aloud. It was Christian’s reply, and it was openly hostile. He had written that he took great offense at the tone of Tycho’s appeal, which Tycho had composed “audaciously and not without5 great lack of understanding, as if We were to render account to you concerning why and with what cause We made changes on Our and the Crown’s estates.” Tycho had “not blushed to [write] as if you were Our equal. . . . from this day on, We shall be otherwise respected by you if you expect to find in Us a gracious lord and king.” Christian also took offense at Tycho’s going abroad with “his woman and children” (a reference to Kirsten’s low status) to beg from others, implying before all the world that Christian and Denmark were not wealthy enough to support them.

  A woodcut of Wandsburg Castle, dating from 1590.

  It was a brutal letter and clearly not drafted carelessly in a fit of pique. It confronted Tycho’s appeal point by point: Tycho had abused his position as a nobleman by appropriating incomes and tithes of the Hven church; he had failed to maintain the church buildings; he had not paid the parson a suitable wage; he had permitted economic abuse of his tenants. Since all these charges had indeed been brought formally against Tycho, and the record was not yet clear whether he was guilty, the king may have had substantial reason for outrage at the argument that the crown had unfairly transferred fiefs from Tycho. The letter went on to insinuate that there was reason to doubt Tycho’s claim that the transfer of fiefs had so impoverished him that he had had to sell his right in Knutstorp to support his astronomy, in the interest of the honor of Denmark and the future of science. News had reached the king that Tycho had money “to lend in thousands of dalers to lords and princes, for the good of your children and not for the honor of the kingdom or the promotion of science.” As for Tycho’s willingness to return on “reasonable terms,” Christian replied, “If you would serve as a mathematicus and do what he ought to do, then you should first humbly offer your service and ask about it as a servant ought to do . . . afterwards We shall know how to declare our will.” Meanwhile, Christian would not “trouble Ourselves whether you leave the country or stay in it.”

  Whatever ambivalence Tycho had about returning, and however much he had been expecting the worst, this reply was a blow. Living in exile and seeking a new position were no easy prospect at his age. As he expressed his misgivings in a letter to a Danish friend: “No doubt the time will come6 when experience and circumstances will render [Christian] more clear-eyed and sensitive . . . about what is of greater value to his realm than other useless things . . . but it will be too late for me and my researches.”

  Characteristically, Tycho took refuge in his self-image as one of the great men of history, many of whom, including the poet Ovid, had experienced the bitterness of exile. Tycho wrote an “Elegy to Denmark,”7 102 lines of Latin verse modeled on Ovid’s elegies. After sending a copy of that to Rantzau, he moved quickly to other matters. Though he would not yet cease pressuring the Danish government to restore him to Hven, it was all the more urgent that Wandsburg become a temporary Uraniborg while he sought a new patron.

  The day after venting his rage toward King Christian in the elegy, Tycho resumed his systematic observations of the planets and moved forward toward the publication of a splendid new book. Astronomiae Instauratae Mechanica would describe his instruments in words and woodcuts, document their superiority, and tell of his life, his work, and Uraniborg. Tycho saw this as a sort of extended résumé, but in a lavish, elegantly bound printing suitable to be a gift for kings—a powerful credential in Tycho’s patron search. By the end of the year he was busy writing a dedication for the book to Rudolph II, emperor of the Holy Roman Empire, who ruled from his court in Prague, and whose imperial mathematician was Ursus.

  Tycho planned to use his star catalog as another credential. During the last weeks on Hven he had driven himself and his assistants, trying to finish “filling out the thousand,” in other words, to bring his catalog up to the thousand stars that were usually included in the ancient star catalogs. Now, at Wandsburg, the assistants who had accompanied him into exile or rejoined him (possibly only two of them at this time) labored in the tower to complete that task. Neither Tycho nor his heirs ever published the catalog, perhaps because Tycho was unable to achieve the quality he hoped for by cross-checking independent sets of data. However, though the catalog may not have been, by his standards, good enough to publish, it was good enough to impress European rulers. Tycho produced an elegant manuscript version, hand-lettered on vellum parchment.fn1

  At New Year 1598, Tycho dedicated this volume also to Emperor Rudolph as a gift and entrusted its safe journey to Prague to his sixteen-year-old son Tycho, who was starting out on travels for his own education. In his search for a new patron, the elder Tycho had chosen his target.

  Twenty-two years earlier, when he had attended Rudolph’s coronation as King of the Romans in the lead-up to becoming Holy Roman Emperor, Tycho had made a friend of Thaddeus Hagecius, Rudolph’s personal physician. They had continued to correspond over the years during which Hagecius had become one of Rudolph’s most trusted advisors. Hagecius was one of the men to whom Tycho had written about his Mars parallax observations. Now, by letter, Tycho consulted Hagecius about whom to approach at the court in Prague and how to go about it. Tycho had additional contacts there as well, including the imperial librarian (an acquaintance since student days in Basel) and several Austrian noblemen who had visited Uraniborg. There were others not powerful enough to influence imperial decisions who nevertheless were useful in keeping Tycho well informed.

  As the elegant pages of his new Mechanica came off the press in the spring of 1598, Tycho had the books bound differently depending on where he planned to send them, some in leather, others in vellum or fine silk with metal clasps. Perspective drawings that painstakingly copied nature and drew the viewer deep into the picture were the height of artistic fashion in the late sixteenth century, and the thirty-one woodcuts and engravings in Tycho’s book—quite apart from their value in documenting and showing off the wonders of his instruments—were superb examples of this “mannerist” style. Far more than a scientific treatise, Mechanica was intended to be the equivalent of a coffee-table book for the palaces of Europe.

  Former assistants who were noblemen were soon carrying opulent copies of Mechanica and the star catalog to princes, bishops, archbishops, and other rulers who had valuable contacts in Denmark and Prague. Tycho’s carefully chosen couriers had access to the courts of Europe and could converse comfortably with princes and other rulers about Tycho’s achievements and stir them to outrage concerning his current tribulations. Franz Tengnagel, the Westphalian nobleman who at the age of nineteen had joined Tycho at Hven in 1595 and remained with him until the day before Tycho left Copenhagen, had rejoined him in exile. Though now only twenty-two years old, Tengnagel was an extraordinarily effective courier. Tycho sent him to Archbishop Elector Ernest of Cologne, whom Rantzau knew to be a particularly influential cousin of Emperor Rudolph. Not only did Tengnagel win the archbishop’s deepest sympathy and generous promises of assistance for Tycho, but he came away with a gold medallion and a fine riding horse for himself as well.

  The archbishop, true to his word, wrote two letters—one addressed to Rudolph, assuring him that “the whole German fatherland”8 would bless him if he granted generous patronage to Tycho Brahe,
the “unique and most laudable restorer of the sciences”; the second to the emperor’s closest adviser, Johannes Barvitius, pressing Barvitius to facilitate Tycho Brahe’s case. These letters were put into Tycho’s hands so that he could present them himself. Tycho, meanwhile, covered his bases by sending gift books to other parts of his network. Prince Maurice of Orange promised to try to arrange public support for Tycho in Holland.

  At the same time, Tycho was rebuilding his staff. He had kept in touch with many other former assistants besides those he was using as noble couriers, and he wrote to some of these at German universities, inviting them to join him. Wandsburg was on one of the most direct routes from Denmark to the rest of Europe, and as word spread of Tycho’s new address, many young Danish scholars stopped by for visits. They gave him repeated boosts for his ego and another means of keeping abreast of what was happening all over the Continent, not only in politics but also in the scholarly world.

  In early March one such visitor arrived, bringing Tycho two books and a letter. One of the books raised Tycho’s hackles the moment he saw the author’s name: Ursus, none other than the Nicolaus Reimers Bär who had been such an obnoxious visitor at Uraniborg in 1584 and had caused Tycho so much worry and grief since. Though Ursus had never again been a presence at Tycho’s table or nosing about in his library, he had made a habit of surfacing now and again, claiming Tycho’s planetary system as his own and referring to Tycho as more astrologer than astronomer and not likely to achieve anything important. Since the scholarly world was well monitored by Tycho’s network of former students and colleagues, none of these incidents escaped Tycho’s ears.