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Mästlin, Michael


(b. Göppingen, Germany, 30 September 1550; d. Tübingen, Germany, 20 October 1631)


Earthshine was correctly explained for the first time in print by Mästlin.1 He matriculated at Tübingen University on 3 December 1568 and received the B.A. (30 March 1569) and M.A. (1 August 1571) before entering the theological course.2 To his reprint of Erasmus Reinhold’s Prussian Table, Mästlin added a brief appendix in 1571, and his 1573 essay on the nova of 1572 was impressive enough to be incorporated in its entirety into the Progymnasmata of Tycho Brahe.3 Lacking observational instruments, Mästlin stretched a thread through the nova and two pairs of previously known stars. He took the celestial longitude and latitude of these four fixed points directly from the star catalog of Copernicus, of whose Revolutions he had acquired a copy in 1570. (Mästlin’s heavily annotated copy of the Revolutions is preserved at Schaffhausen, Switzerland.) The intersection of the arcs of the great circles passing through the two pairs of his reference stars gave Mästlin the position of the 1572 nova, and its nondisplacement from them convinced him that it was indeed a new star; thus, coming-into-being could occur in heaven as well as on earth, contrary to the traditional dogma.

Having served as the assistant to Philipp Apian (1531–1589), professor of mathematics at Tübingen, Mästlin replaced him when Apain went on leave in 1575. This arrangement was not renewed, however, for on 24 October 1576 Mästlin was appointed to a Lutheran pastorate in Backnang. In April 1577 he married Margaret Grüinger, who bore him three daughters and three sons.4 Ludwig became a physician after enrolling at Tübingen on 26 February 1594 and obtaining the B.A. on 5 April 1598 and the M.A. on 13 February 1600.5 In that year Michael, Jr., a painter, ran away from home and was later said to be hiding among the Jesuits.6 Margaret married Tobias Olbert (M. A., Tübingen, 15 February 1598) on 7 December 1602; Anna Maria also married a Lutheran clergyman, Johann Wolfgang Mügling; and Sabina married Burckhardt Rümelin, a Tübingen law student in 1606 and court attorney in 1624.7.

Mästlin was designated professor of mathematics at Heidelberg University on 19 November 1580.8 In discussing that year’s comet he declared that the unsoundness of the Aristotelian cosmology had been revealed to him by three great celestial events occurring over a period of eight years: the 1572 nova and the comets of 1577 and 1580.

Having failed to detect any perceptible parallax in the comet of 1577, Mästlin concluded that it was not a sublunar but, rather, a supralunar body. Remarking that “according to Abū Ma’shar, who flourished about A.D. 844, a comet was seen above the sphere of Venus,” he asked, “What would have been the physical cause of this [phenomenon], if we are to believe that comets have no place other than the region of the [four] elements?”9 Rejecting the conventional classification of comets as metrological phenomena, he located the comet of 1577 in the sphere of Venus.

Nevertheless, in his Epitome of Astronomy, an introductory textbook begun while he was still a student at Tübingen and so popular that it ran through seven editions between 1582 and 1624, Mästlin expounded the traditional view as easier for beginners to understand. He advised Protestant governments to reject the Gregorian calendar as a papal scheme to regain control over territories that had escaped from its grasp. All of his books and writings appeared on the Index of Pope Sixtus V in 1590.10

In a public address at Tübingen University on 22 September 1602,on the basis of his chronological researches Mätlin put Jesus’ birth more than four years before the conventional date.11 On 23 May 1584 he had replaced Apain, who had been dismissed for refusing to sign the oath of religious allegiance; he later bought Apian’s library from the latter’s widow.12 Mästlin, a man of slight build, unlike the massive ancestor from whom his surname was derived,13 was elected dean of the Tübingen Arts Faculty eight times between 1588 and 1629. He taught there for forty-seven years, until his death in 1631.

His first wife having died on 15 February 1588, on 28 January 1589 Mästiln married Margaret Burckhardt (19 March 1564–18 February 1622), who bore him nine children.14 Sabina, the second Mästlin daughter to bear this name, was buried on 9 July 1596, before attaining the age of seven, and a third Sabina was born on 22 June 1599.15 A Second Margaret, christened on 16 December 1604, died on 31 August 1609.16 Augustus, born on 13 January 1598, died on 16 February 1598.17 Anna Dorothea married a Lutheran clergyman, Andrew Osiander (M.A., Tüngen, 1610), in 1614.18 Gottfried, baptized on 12 October 1595, received his B.A. at Tübingen on 31 March 1612, his M.A. on 16 August 1615, and became a professor of languages there in 1627.19 Matthew acquired his B.A. at Tüingen on 17 March 1619 and the M.A. on 20 February 1622. He married on 24 November 1622; taught school at Gerlingen; and worked as a caretaker in Knittlingen, where he was buried on 6 February 1661.20

In his 1578 discussion of the comet of 1577, Mästlin announced his “adoption of the cosmology of Copernicus, truly the foremost astronomer since Ptolemy.” In 1632 Galileo attributed his acceptance of Copernicanism to two or three lectures, delivered shortly after he had completed his philosophy course, by a foreign professor whose identity (or very existence) in uncertain.21 Hence in 1650 Gerhard Johann Voss (1577–1649) posthumously initiated the legend—which has been uncritically repeated by influential writers for centuries—that the foreigner responsible for Galileo’s Copernicanism was Mästlin.22 The latter, however, was really responsible for the Copernicanim of Johannes Kepler, who attended Mästlin’s classroom lectures at Tübingen and heard him expound the superiority of the Copernican astronomy over the Ptolemaic.23 The pupil-teacher relationship between Kepler and Mästlin ripened into a lifelong affectionate friendship, each sincerely acknowledging the other’ valuable assistance. No finer example of the educational process at its best can be found in the entire history of science.


1. The key passage was translated into English by Edward Rosen, Kepler’s Conversation, 117–119, 157.

2.Die Matrikeln der Universität Tübingen I (Stuttgart, 1906), 487.

3. Tycho Brahe, Opera omnia, III (Copenhagen, 1916) 58–62.

4. Karl Steiff, “Der Tübinger Professor …,” 51–53.

5.Matrikeln … Tübingen, 1, 708; Johannes Kepler, Gesammelte Werke, XIII, 211; 119–121, 232;527–528.

6. Kepler, op. cit., XIV, 157; 73–82, 354;473–475.

7.Diarium Martini Crusii, III(Tübingen, 1958), 515;25–26; Matrikeln …Tübingen 1, 707; II. 7.Steiff. op. cit., 53, erroneously assigned this Sabina to Mätlin’s second marriage.

8.Die Matrikel der Universitä Heidelberg, II (Heidelberg, 188+6), 92.

9. Mästlin’ statement about Abü Ma’shar Islam’s foremost astrologer, was undoubtedly based on Cardano’s Astronomical Aphorisms, published as a supplement to Hieronumi Cardani Libelli V (Nuremberg, 1547), as cited by Willy Hartner, Oriens-Occidens (Hildsheim, 1968), 503.

10. Heinrich Reusch, ed., Die Indices librorum prohibitorum des sechszehnten Jahrhunderts (Tübingen, 1896; repr, Nieuwkoop, 1961), 504, 566.

11. Kepler, op. cit., XVIII, 56; 100–103.

12.Matrikeln … Tübingen,I,624; Siegmund Günther, Peter und Philipp Apian (Amsterdam, 1967, repr. of 1882 ed.), 107–109; Ernst Zinner, Entstchung und Ausbreitung der Correnicanischen Lehre, 453

13. Edward Rosen, Kelper’s Somnium, 64–65; H. M. Decker, “Die Athnen des Astronomen Mästlin,” 103–104.

14. W. Bardili, “Ergänzungen zur ‘Geistesmutter,’” 114.

15.Diarium…Crusü, I, 128:18–20; Kepler, op. cit., XIII, 368:28; XIV, 43:5, 463:5.

16. K. E. von Marchtaler, “Ein Beitrag zur Familienforschung Mästlin,” 179.

17. Kepler, op. cit., XIII, 184:179–180, 209:12–14.

18. “1604” in Steiff, op. cit., 53, is a misprint; Matrikeln… Tübingen, 11, 41.

19.Matrikeln…Tübingen, II, 57.

20.Ibid., 72; Marchatlaer, op. cit., 179–180.

21. Galileo Galilei, Opere, national ed., VII (Florence, 1897; repr. 1968), 154:5–10.

22. G. J. Voss,De universae mathesios natura et consitutione liber, cui subjungitur chronologia mathematicorum (Amsterdam, 1650), 192.

23. Kepler, op. cit., I, 9:11–21.


I. Original Works. Writings published under Mästlin’s name are Ephemeris nova anni 1577 (Tübingen, 1576); Observatio et demonstratio cometae aetherei, qui anno 1577 et 1578…apparuit (Tübingen, 1578); Ephemerides novae ab anno…1577ad annum 1590 (Tübingen, 1580), preceded by Regiomontanus’ brief Commentary on the Ephemerides and Mästlin’s additions thereto, as well as a portrait of Mästlin, aged twenty-eight; Consideratio et observatio cometae aetherei astronomica, quo anno 1580… apparuit (Heidelberg, 1581), with the same portrait as in the 1580 work; De astronomiae principalibus et primis fundamentis disputatio(Heidelberg, 1582), the respondent on 20 January 1582 being Jeremiah Jecklin or Jacobus of Ulm (M.A., Heidelberg, 24 July 1582)—the title is preceded by “Divino rectoris astrorum favente numine,” a religious formula which has been listed as though it identified a separate publication; De astronomiae hypothesibus sive de circulis sphaericis et orbibus theoricis deisputatio (Heidelberg, 1582), the repondent being Matthias Mener (M. A., Heildelberg, 19 Feb. 1583); Epitome astronomiae (Heidelberg, 1582; Tübingen, 1588, 1593, 1597, 1598, 1610, 1624); Aussführlicher und gründtlicher Bericht von der … Jarrechnung (Heidelberg, 1583), cited by Mästlin in a later calendar tract written in Latin as his “Dialexis germanica,” which has sometimes been registered as though it were a separate publication, also repr., with additions, in Nothwendige und grüdtliche Bedenckhen von dem…Kalender (Heidelberg, 1584); Alterum examen novi pontificialis Gregoriani Kalendarii (Tübingen, 1586); and Defensio alterius sui examinis (Tübingen, 1588).

He also wrote Tres disputationes astronomicae et geographicae (Tübingen, 1592): De climatibus (the respondent being Wolfgang Hohenfelder), De diebus naturalibus et artificialibus (the respondent being Ludwig Hohenfelder), De zonis (the respondent being George Achatius Enenckel)—each of these disputations has its own title page and separate pagination; Disputatio de eclipsibus solis et lunae (Tübingen, 1596), the respondent on 15 Jan. 1596 being Marcus Hohenfelder; Geographische Landtafel, StuttgartRome (Reutlingen, 1601); Disputatio de multivariis motuum planetarum in coelo apparentibus irregularitatibus, seu regularibus inaequalitatibus, earumque causis astronomicis (Tübingen, 1652), listed in Jean Graesse, Trésor de livres rares, IV (Dresden, 1863), 333, and Poggendroff, II, 170. Samuel Hafenreffer, ed. (Tübingen, 1641–1646)—Hafenreffer’s copy of the Mästlin MS had been approved by the author; Synopsis chronologiae sacrae, Johann Valentin Andreae, ed. (Lüneburg, 1642), recorded by Jacob Friderich Reimann, Versuch einer Einleitung in die historiam literariam, III, pt. 2 (Halle, 1710), 369–370; and Perpetuae dilucidationes tabularum Prutenciarum coelestium motuum (Tübingen, 1652), listed in Jean Graesse, Trésor de livres rares, IV (Dresden, 1863), 333, and Poggendorff, II, 170.

Mästlin’s writings published in works by other authors are “Observatio mathematica,” appended to Nicodemus Frischlin, Consideratio novae stellae, quae mense Novembri, anni…1572…apparuit (Tübingen, 1573); “Demonstratio astronomica loci stellae novae,” completed on 4 Mar. 1573, in Tycho Brahe, Astronomiae instauratae progymnasmata (Prague, 1602), pt. 3, ch. 8; “De dimensionibus orbium et sphaerarum coelestium,” in Johannes Kepler, Mysterium cosmographicum (Tübingen, 1596), 161–181; autobiography, dated 23 Sept. 1609, in Hermann Staigmüller, “Württembergische mathematiker,” in Württembergische Vierteljahrshefte für Landesgeschichte, 12 (1903), 227–256, see 234–235; appendix to a proposed ed. of Copernicus written in 1621, in Christian Frisch, ed., Joannis Kepleri astronomi opera omnia, I (Frankfurt Erlangen, 1858), 56–58; and “Observationes Moestlinianae,” in Lucius barrettus (Albert Curtius), Historia coelestis (Augsburg, 1666), esp. lxxv-lxxvi-according to the Paralipomena (at sig. Zzzzz2r), these observations, written in Mästlin’s own hand, were transferred by Wilhelm Schickard (the author of a [lost?] funeral oration for Mästlin) to a MS forming part of a collection bought for the Holy Roman Emperor Ferdinand III and preserved in the National Library, Vienna.

Original writings erroneously listed as printed, although still in MS, are “Apologia examinum suorum” (or “Examina, eorundemque apologia”), the title of a work projected by Mästlin in answer to Clavius’ attack on Aussführlicher und gründtlicher Bericht von der…Jarrechnung, Alterum examen novi pontificialis Gregoriani kalendarii, and Defensio alterius sui examinis was registered in the book fair catalog for 1593, which presence led bibliographers to list it as though it had been printed at Tübingen in 1583 (or 1597)—acutally, Mästlin never finished writing this, which remains a torso in Vienna, National Library Codex 12411 (E. Zinner, Entstehung und Ausbreitung…, 435, no. 151); “Horologiorum solarium sciotericorum in superficiebus planis descriptionis et delineationis universalis informatio,” which, although it has been listed as a book printed at Tübingen in 1590, is actually an unpublished MS written by the hand of Gottfried Mästlin, dated 20 July 1613, and preserved in the library of Erlangen University: Katalog der Handschriften der Universitätsbibliothek Erlangen, Hans Fischer, ed., II (Erlangen, 1936), 485, no. 838; and “De cometa anni 1618” (Tübingen, 1619) or “Astronomischer Discurs, von dem Cometon, so in Anno 1618 im November zu erscheinen angefangen und bis Februar dies 1619. Jars am Himmel gesehen worden” (Tübingen, 1619) is listed as printed in both Latin and German but the unpublished MS in German, ready for the printer, still lies in the Württembergische Landesbibliothek, Stuttgart, Codex math. Q. 15a-b.

Unpublished MSS, ready for the printer, are “Iudicium … de opere astronomico D. Frischlini,” dated 18 Jan. 1586 (David Friderich Strauss, Leben und Schriften des Dichters und Philologen Nicodemus Frischlin [Frankfurt, 1856], 330); “Modus, ratio et fundamenta compositionis tabularum directionum Regiomontani et Reinholdi,” Stuttgart Landesbibliothek, Codex matt. Q. 15a-b; “Commentarius in 1. et 2. librum Euclidis cum demonstrationibus regularum algebraicarum,” Vienna, National Library, Codex 12411 (E. Zinner, Entstehung und Ausbreitung…, 440, no. 260); “Ememdatio sphalmatum typographicorum in Opere Palatino quodam geometrico et in Magno Canone Rhetici, nec non demonstratio, canonem tangentium et secantium in eodem Magno Canone Rhetici iuxta finem quadrantis minus exactum esse,” Vienna, National Library (Tabulae codicum manu scriptorum praeter graecos et orientales in Bibliotheca Palatina Vindobonensi asservatorum, VI [Vienna, 1873], 253, no. 10913); and “Tractatus brevis de dimensione triangulorum rectilineorum et sphaericorum,” written by the hand of Gottfried Mästlin, dated Oct. 1612, preserved at Erlangen—see Katalog der Handschriften der Universitätsbibliothek Erlangen, II, 485, no. 839.

Other unpublished MSS are listed in Vienna, National Library, Codex 12411; Tabulae codicum… in Bibliotheca Palatina Vindobonensi; Katalog der Handschriften der Universitätsbibliothek Erlangen; Die historischen Handschriften der k. öffentlichen Bibliothek zu Stuttgart, W. von Heyd, ed., I (Stuttgart, 1889), 257: Codex hist. fol. 603, Mästlin’s correspondence with Johann Weidner; 283: Codex hist. fol. 657, biography of Mästlin by Johann Gottlieb Friedrich von Bohnenberger (1765–1831); Codex math. fol. 14b and Q. 15a-b; Verzeichnis der Handschriften im deutschen Reich, II, Die Handschriften der Universitätsbibliothek Graz, Anton Kern, ed., I (Leipzig, 1939), 82, no. 159 (15): a letter from Johann Reinhard Ziegler in Mainz to Paul Guldin in Rome, dated 5 Apr. 1611, regarding Mästlin’s acquisition of a telescope; andKataloge der Herzog-August-Bibliothek Wolfenbüttel, Die Augusteischen Handschriften II (Frankfurt, 1966 [repr. of 1895 ed.]), 118–120, no. 2174: 15.3.Aug. fol.—also see Ernst Zinner, Verzeichnis der astronomischen Handschriften des deutschen Kulturgebietes (Munich, 1925), 217–219.

Published correspondence consists of Mästlin’s letters to, from, and about Kepler, in Johannes Kepler, Gesammelte Werke (Munich, 1937– ), part of which was trans. into German in Johannes Kepler in seinen Briefen, Max Caspar and Walther von Dyck, eds., 2 vols. (Munich-Berlin, 1930); and five letters to Mästlin from Simon Marius, in Ernst Zinner, “Zur Ehrenrettung des Simon Marius,” in Vierteljahrsschrift der Astronomischen Gesellschaft (Leipzig), 77 (1942), 40–45.

Works edited by Mästlin are Erasmus Reinhold, Prute nicae tabulae (Tübingen, 1571), with an appendix, dated 1571, by Mästlin on p. 143; and George Joachim Rheticus, Narratio prima, in Johannes Kepler’s Mysterium cosmographicum (Tübingen, 1596), 93–160, with Mästlin’s preface, dated 1 Oct. 1596, at 86–90, and numerous notes by him in the margins.

A misattribution is Problema astronomicum: Die Situs der Sternen, Planetarum oder Cometarum zu observiren ohne Instruments (n.p., 1619). The Latin original of this trans. into German by Matthew Beger was misattributed to Mästlin by J. C. Houzeau and Albert Lancaster, Bibliographie gènèrale de l’astronomie, I, pt. 1 (Brussels, 1887; repr. London, 1964), 603, where the work of Beger (miscalled Begern) is incorrectly listed as a translation of Mästlin’s Tres disputationes… Actually, Beger translated from Adriaan Metius’ Astronomiae universae institutiones (Franeker, 1606–1608) an excerpt in which Metius discussed Mästlin’s method of observing without the aid of any instruments.

II. Secondary Literature. See Peter Aufgebauer, “Die Gregorianische Kalenderreform im Urteil zeitgenössischer Astronomen,” in Sterne, 45 (1969), 118–121; Walter Bardili, “Ergänzungen zur ‘Geistesmutter,’” inBlätter für Württembergische Familienkunde, 8 (1939–1941), 113–119; J. G. F. von Bohnenberger, “Michael Mästlin,” in Württem bergische Familienkunde, 8 (1939–1941), 102–104; Siegmund Günther,Beiträge zur Geschichte der neueren Mathe matik (ansbach, 1881), 15–25; and “Mästlin,” in Allgemeine deutsche Biographic, XX, 575–580, also repr. (Berlin, 1970), XLV, 669; C. Doris Hellman, The Comet of 1577 (New York, 1944; repr. 1971), 137–159; Johannes Kepler, Gesammelte Werke (Munich, 1937–); and viktor Kommerell, “Michael Mästlin,” in Schwäbische Lebensbilder IV (Stuttgart, 1948), 86–100.

Also see Paul Löffler, “Michael Mästlin zu seinem 300. Todestag,” in Tübinger Chronik-Amtsblatt für den Oberamtsbezirk Tübingen, 87 , no. 245 (20 Oct. 1931), 4r; Kurt Erhard von Marchtaler, “Ein Beitrage zur Familienforschung Mästlin,” in Blätter Für Württembergische Familienkunde, 8 (1939–1941), 178–180; Edward Rosen, “Kepler and the Lutheran Attitude Toward Copernicanism,” in Vistas in Astronomy (in press); Kepler’s Somnium (Madison, Wis., 1967), xvi, repro. of an oil portrait of Mästlin painted in 1619; Karl Steiff, “Der Tübinger Professor der Mathematik und Astronomie Michael Mästlin,” in Literarische Beilage des Staats-Anzeiger für Württemberg (30 Apr. 1892), 49–64, 126–128; Ernst Zinner, Entstehung und Ausbreitung der Coppernicanischen Lehre (Erlangen, 1943); and Edward Rosen, Kepler’s Conversation with Galileo’s Sidereal Messenger (New York-London, 1965).

Edward Rosen

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