Regiomontanus

Regiomontanus
Regiomontanus
Born	6 June 1436(1436-06-06) Unfinden, now part of Königsberg, Bavaria
Died	6 July 1476(1476-07-06) (aged 40) Rome
Nationality	German
Fields	Mathematics, astronomy, astrology
Alma mater	University of Vienna

Johannes Müller von Königsberg (6 June 1436 – 6 July 1476), today best known by his Latin toponym Regiomontanus, was a German mathematician, astronomer, astrologer, translator, instrument maker and Catholic bishop.

He was born in the Franconian village of Unfinden (now part of Königsberg, Bavaria) — not in the more famous East-Prussian Königsberg.

He was also known as Johannes der Königsberger (Johannes of Königsberg). His writings were published under the toponym Joannes de Monte Regio. The name Regiomontanus was first coined by Phillip Melanchthon in 1534, fifty-eight years after his death.

Life

Plaque at Regiomontanus' birthplace

At eleven years of age, he became a student at the university in Leipzig, Saxony. In 1451 he continued his studies at Alma Mater Rudolfina, the university in Vienna, Austria. There he became a pupil and friend of Georg von Peurbach. In 1452 he graduated BA and was awarded his “magister artium” (Master of Arts) at the age of 21 in 1457 and held lectures in optics and ancient literature.

He continued to work with Peuerbach learning and extending the then known areas of astronomy, mathematics and instrument making until Peuerbach's death in 1461.

In 1460 the papal legate Basilios Bessarion came to Vienna on a diplomatic mission, a humanist scholar and great fan of the mathematical sciences Bessarion sought out Peuerbach's company. George of Trebizond who was Bessarion's philosophical rival had recently produced a new Latin translation of Ptolemy's Almagest from the Greek, which Bessarion, correctly, regarded as inaccurate and badly translated, so he asked Peuerbach to produce a new one. Peuerbach's Greek was not good enough to do a translation but he knew the Almagest intimately so instead he started work on a modernised, improved abridgement of the work. Bessarion also invited Peuerbach to become part of his household and to accompany him back to Italy when his work in Vienna was finished. Peuerbach accepted the invitation on the condition that Regiomontanus could also accompany them. However Peuerbach fell ill in 1461 and died only having completed the first six books of his abrdgement of the Almagest. On his death bed Peuerbach made Regiomontanus promise to finish the book and publish it.

In 1461 Regiomontanus left Vienna with Bessarion and spent the next four years travelling around Northern Italy as a member of Bessarion's household, looking for and copying mathematical and astronomical manuscripts for Bessarion, who possessed the largest private library in Europe at the time. Regiomontanus also made the acquaintance of the leading Italian mathematicians of the age such as Giovanni Bianchini and Paolo dal Pozzo Toscanelli who had also been friends of Peuerbach during his prolonged stay in Italy more than twenty years earlier. During his time in Italy he completed Peuerbach's Almagest abridgement, Epytoma in almagesti Ptolemei. In 1464, he completed De Triangulis omnimodus. De Triangulis (On Triangles) was one of the first textbooks presenting the current state of trigonometry and included lists of questions for review of individual chapters. In it he wrote:

“You who wish to study great and wonderful things, who wonder about the movement of the stars, must read these theorems about triangles. Knowing these ideas will open the door to all of astronomy and to certain geometric problems.”

His work on arithmetic and algebra, Algorithmus Demonstratus, was among the first containing symbolic algebra.^[1] In 1465, he built a portable sundial for Pope Paul II.

In Epytoma in almagesti Ptolemei, he critiqued the translation of Almagest by George of Trebizond, pointing out inaccuracies. Later Nicolaus Copernicus would refer to this book as an influence on his own work. He went to work for János Vitéz, archbishop of Esztergom. There he calculated extensive astronomical tables and built astronomical instruments. Later he went to Buda, and the court of Matthias Corvinus of Hungary, for whom he built an astrolabe, and where he collated Greek manuscripts for a handsome salary.^[2]

In 1471 he moved to the Free City of Nuremberg, in Franconia, then one of the Empire's important seats of learning, publication, commerce and art. He worked together with the humanist and merchant Bernhard Walther. Contrary to popular belief there is no evidence that Regiomontanus ever erected an observatory, however he did found the world's first scientific printing press and in 1472 he published the first printed astronomical textbook, the Theoricae novae Planetarum of his teacher Georg von Peurbach.

In 1475 he went to Rome to work with Pope Sixtus IV on calendar reform. Regiomontanus died of unknown causes in Rome, July 6, 1476, a month after his fortieth birthday. According to a rumor repeated by Gassendi in his Regiomontanus biography he was assassinated by relatives of George of Trebizond whom he had criticized in his writings. More likely he died in an epidemic raging in Rome at the time.

A prolific author, Regiomontanus was internationally famous in his lifetime. Despite having completed only a quarter of what he had intended to write, he left a substantial body of work. Nicolaus Copernicus' teacher, Domenico Maria Novara da Ferrara, referred to Regiomontanus as having been his own teacher. There is speculation that Regiomontanus had arrived at a theory of heliocentrism before he died; a manuscript shows particular attention to the heliocentric theory of the Pythagorean Aristarchus, mention was also given to the motion of the earth in a letter to a friend. ^[3]

In 1561, Daniel Santbech compiled a collected edition of the works of Regiomontanus, De triangulis planis et sphaericis libri quinque (first published in 1533) and Compositio tabularum sinum recto, as well as Santbech's own Problematum astronomicorum et geometricorum sectiones septem. It was published in Basel by Henrich Petri and Petrus Perna.

The crater Regiomontanus on the Moon is named after him.

Astrology

One biographer has claimed to have detected a decline in Regiomontanus' interest in astrology over his life, and came close to asserting that Regiomontanus had rejected it altogether.^[who?] But more recent commentators have suggested that the occasional expression of skepticism about astrological prognostication reflected a disquiet about the procedural rigour of the art, not about its underlying principles. It seems plausible that, like some other astronomers, Regiomontanus concentrated his efforts on mathematical astronomy because he felt that astrology could not be placed on a sound footing until the celestial motions had been modeled accurately.

In his youth, Regiomontanus had cast horoscopes (natal charts) for famous patrons. His Tabulae directionum, completed in Hungary, were designed for astrological use and contained a discussion of different ways of determining astrological houses. The calendars for 1475-1531 which he printed at Nuremberg contained only limited astrological information—a method of finding times for bloodletting according to the position of the moon; subsequent editors added material.

But perhaps the works most indicative of Regiomontanus' hopes for an empirically sound astrology were his almanacs or ephemerides, produced first in Vienna for his own benefit, and printed in Nuremberg for the years 1475-1506. Weather predictions and observations were juxtaposed by Regiomontanus in his manuscript almanacs, and the form of the printed text enabled scholars to enter their own weather observations in order to likewise check astrological predictions; extant copies reveal that several did so.

Regiomontanus' Ephemeris would be used in 1504, by a Christopher Columbus stranded for a year on Jamaica, to intimidate the natives into continuing to provision him and his crew from their own scanty food stocks. Columbus accomplished this when he successfully predicted a lunar eclipse for 29 February 1504.^[4]

Regiomontanus did not live to produce the special commentary to the ephemerides that he had promised would reveal the advantages the almanacs held for the multifarious activities of physicians, for human births and the telling of the future, for weather forecasting, for the inauguration of employment, and for a host of other activities, although this lack was again made good by subsequent editors. Nevertheless Regiomontanus' promise suggests that he was convinced of the validity and utility of astrology as his contemporaries.

It seems more than plausible that Regiomontanus did believe in astrology, as he invented his personal method of sky map dividing, also known as house, Regiomontanus house system.

Criticism

Much of the material on spherical trigonometry in Regiomontanus' On Triangles was taken directly and without credit from the twelfth-century work of Jabir ibn Aflah otherwise known as Geber, as noted in the sixteenth century by Gerolamo Cardano.^[5]

See also

• Regiomontanus' angle maximization problem

Notes

Literature

• Irmela Bues, Johannes Regiomontanus (1436–1476). In: Fränkische Lebensbilder 11. Neustadt/Aisch 1984, pp. 28–43
• Rudolf Mett: Regiomontanus. Wegbereiter des neuen Weltbildes. Teubner / Vieweg, Stuttgart / Leipzig 1996, ISBN 3-8154-2510-7
• Helmuth Gericke: Mathematik im Abendland: Von den römischen Feldmessern bis zu Descartes. Springer-Verlag, Berlin 1990, ISBN 3-540-51206-3
• Günther Harmann (Hrsg.): Regiomontanus-Studien. (= Österreichische Akademie der Wissenschaften, Philosophisch-historische Klasse, Sitzungsberichte, Bd. 364; Veröffentlichungen der Kommission für Geschichte der Mathematik, Naturwissenschaften und Medizin, volumes 28–30), Vienna 1980. ISBN 3-7001-0339-5
• Samuel Eliot Morison, Christopher Columbus, Mariner, Boston, Little, Brown and Company, 1955.
• Ralf Kern: Wissenschaftliche Instrumente in ihrer Zeit/Band 1. Vom Astrolab zum mathematischen Besteck. Köln, 2010. ISBN 978-3-86560-865-9

External links

• ‹ The template below (PND) is being considered for deletion. See templates for discussion to help reach a consensus.›

Regiomontanus in the German National Library catalogue (German)

• (in German) Regiomontanus. Biographisch-Bibliographisches Kirchenlexikon (BBKL). http://www.bautz.de/bbkl/r/regiomontanus.shtml. 
• Günther (1885) (in German). "Johannes Müller Regiomontanus". In Allgemeine Deutsche Biographie (ADB). 22. Leipzig: Duncker & Humblot. pp. 564–581.
• Folkerts, Menso ; Kühne, Andreas (1955) (in German). "Regiomontan(us)". In Neue Deutsche Biographie (NDB). 2. Berlin: Duncker & Humblot. pp. 270 et seq..
• Adam Mosley, Regiomontanus Biography, web site at the Department of History and Philosophy of Science of the University of Cambridge (1999).
• O'Connor, John J.; Robertson, Edmund F., "Regiomontanus", MacTutor History of Mathematics archive, University of St Andrews, http://www-history.mcs.st-andrews.ac.uk/Biographies/Regiomontanus.html .
• Electronic facsimile-editions of the rare book collection at the Vienna Institute of Astronomy
• Regiomontanus and Calendar Reform
• Polybiblio: Regiomontanus, Johannes/Santbech, Daniel, ed. De Triangulis Planis et Sphaericis libri quinque. Basel Henrich Petri & Petrus Perna 1561
• Engl. Biographie bei MacTutor
• Joannes Regiomontanus: Calendarium, Venedig 1485, Digitalisat
• Beitrag bei „Astronomie in Nürnberg“
• Digitalisierte Werke von Regiomontanus — SICD der Universitäten von Strasbourg
•  "Regiomontanus". The American Cyclopædia. 1879. 
•  "Regiomontanus". Encyclopaedia Britannica. 20 (9th ed.). 1886. 
• Online Galleries, History of Science Collections, University of Oklahoma Libraries High resolution images of works by and/or portraits of Regiomontanus in .jpg and .tiff format.