chapter 1 Introduction Miguel A. Granada 1 Christoph Rothmann and Astronomy in Wittenberg We know little about the life of Rothmann outside of his period of employment at Kassel. Although we know that he was born in Bernburg, in the principal- ity of Anhalt, we do not know the date of his birth, only that he must have been born around 1560. While the date and place of his death were uncertain until very recently, this was presumed to have occurred at his place of birth and before 1611, the year in which a treatise of his on the sacraments, the Restitutio sacramentorum, was published posthumously.1 However, recent archival find- ings have led Nils Lenke and Nicolas Roudet to conclude that Rothmann died in Bernburg in the summer of 1601.2 In any case, Rothmann was scientifically inac- tive from September 1590, when he failed to return to Kassel after visiting Tycho at Uraniborg. A reason for this abandonment of his position with the Landgrave may be found in his reported hope that Tycho would be able to provide him with an effective medical treatment for the painful ailment afflicting him.3 Rothmann studied at the University of Wittenberg, where he matriculated in August 1575. No evidence remains of his course of studies or graduation. How- ever, in a letter of his to the Landgrave of 15 November 1585, relating to the comet recently observed, the title of ‘liberalium artium et philosophiae M[agister]’ is adjoined to Rothmann’s signature.4 This is the only known occasion on which 1 Rothmann (1611). 2 The year of Rothmann’s death is documented in the letter his brother Bartholomaeus Roth- mann addressed on 5 March 1602 to Landgrave Moritz: ‘my brother Christoph Rothmann, formerly the mathematician of the father of your princely Grace of praiseworthy memory, died last Summer’ [mein Bruder Christophorus Rothmannus, weyland efg herrn vaters lob- seeligen gedechtnis Mathematicus im vergangenen Sommer mit tode abgangen]. The letter, preserved in the Hessisches Staatsarchiv Marburg (Best. 17d Rothmann Nr. 1), has been edited for publication in Lenke and Roudet (2014). 3 For a biographical sketch, see Granada, Hamel, and von Mackensen (2003), 10–14. On Roth- mann’s visit to Tycho and the abandonment of his position in Kassel, see Goldstein and Barker (1995), Granada (2002b), 183–202. 4 See Appendix 1.4. Rothmann customarily assigned himself only the title of mathematicus. © koninklijke brill nv, leiden, 2014 | doi: 10.1163/9789004260351_002 2 granada this occurred. It is certainly possible that Rothmann had completed his studies in the Faculty of Arts and obtained the title of Magister Artium. Similarly, we may hypothesise that he studied at least some theology—that would explain his posthumous theological treatise—though perhaps without completing a higher degree. In any case, as a student of the arts at Wittenberg, Rothmann would have acquired the solid training in mathematics and astronomy that justified his subsequent activity and employment at Kassel. Wittenberg stu- dents were given solid instruction in these disciplines from the days of Philip Melanchthon (1497–1560) onwards, through the teaching of such instructors as Georg Joachim Rheticus (1514–1574), Erasmus Reinhold (1511–1553), Caspar Peucer (1525–1602), Sebastian Theodoricus (1520–1574), and Johannes Praeto- rius (1537–1616). Several aspects of astronomical activity at Wittenberg at the beginning of the 1570s are worth considering, even leaving to one side the assimilation of the purely technical components of Copernican astronomy—that is, consid- eration of the models of planetary motion from a geometrical rather than a cosmological perspective, according to the so-called ‘Wittenberg interpreta- tion’ of Copernican astronomy.5 Generally significant for the subsequent career of Rothmann, these aspects clarify, in particular, some of the positions adopted by Rothmann in the Dialexis. Johannes Praetorius was professor of higher mathematics at Wittenberg, fol- lowing Sebastian Theodoricus, from 1571 until the beginning of 1575. Contrary to what has customarily been accepted, Praetorius could not have been Roth- mann’s professor.6 In 1578, Praetorius published a treatise on the comet of 1577, in which he supplied a census of earlier comets and devoted particular atten- tion to the new luminary observed in Cassiopeia from November 1572. On the nova, Praetorius affirmed the following: (1) that it was effectively a celestial comet, (2) that it was located in the region of the superior planets or of the stars, as witnessed by its complete lack of parallax, and (3) that it was entirely immobile, save for the daily movement of the whole of the heavens.7 Although 5 The term was coined by Robert S. Westman in his important article, Westman (1975); see now also Barker (2000), and Westman (2011), especially 141–170. 6 See Granada (2006), 131 and n. 38. Before entering the Altdorf Academy in 1576, Praetorius lived for some time in Warsaw. Since Rothmann matriculated at the University of Wittenberg in August 1575, and Praetorius occupied the chair of higher mathematics, this scarcely allows for a direct discipleship. This is also the opinion recently expressed by Robert S. Westman; see Westman (2011), 291. On Praetorius, see Müller (1993a), passim, and Folkerts (1993). 7 Praetorius (1578), sig. B3v: ‘III. This star had no motion, except that which it had in common with the fixed stars. And it always kept the same place which it had at first. IV. Its distance.