Copyright Michael D. Robbins 2005

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"Quite recently I have made observations in the city of Nuremberg for I have chosen it as my permanent home not only on account of the availability of instruments, particularly the astronomical instruments on which the entire science is based, but also on account of the great ease of all sorts of communication with learned men living everywhere, since this place is regarded as the centre of Europe because of the journeys of the merchants."

Regiomontanus, Johann. 1436-1476.
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.

Regiomontanus wrote in 1463:-
No one has yet translated from the Greek into Latin the thirteen Books of Diophantus, in which the very flower of the whole of arithmetic lies hid...


Johannes Müller von Königsberg (June 6, 1436 – July 6, 1476), known by his Latin pseudonym Regiomontanus, was an important German mathematician, astronomer and astrologer. He was born in the Franconian village of Unfinden near Königsberg, Bavaria (not to be confused with the famous East Prussian city of Königsberg (Kaliningrad), nor with Königsberg in der Neumark (Chojna)).

He is also called Johannes Müller, der Königsberger (Johannes Müller of Königsberg). His full Latin name was Joannes de Regio monte, which abbreviated to Regiomontanus (from the Latin for "Königsberg"—"King's Mountain").

At eleven years of age, he became a student at the university in Leipzig, Saxony. Three years later 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 1457 he graduated with a degree of "magister artium" (Master of Arts) and held lectures in optics and ancient literature. He built astrolabes for Matthias Corvinus of Hungary and Cardinal Bessarion, and in 1465 a portable sundial for Pope Paul II. His work with Peurbach brought him to the writings of Nicholas of Cusa (Cusanus), who held a heliocentric view. Regiomontanus, however, remained a geocentrist after Ptolemy. Following Peurbach's death, he continued the translation of Ptolemy's Alimagest which Peurbach had begun at the initiative of Johannes Bessarion. From 1461 to 1465 Regiomontanus lived and worked at Cardinal Bessarion's house in Rome. He wrote De Triangulis omnimodus (1464) and Epytoma in alimagesti Ptolemei. 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."
In the Epytoma he critiqued the translation, pointing out inaccuracies. Later Nicolaus Copernicus would refer to this book as an influence on his own work. In 1467 Regiomontanus left Rome to work at the court of Matthias Corvinus of Hungary. There he calculated extensive astronomical tables and built astronomical instruments.

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 associated with the humanist and merchant Bernard Walther who sponsored the observatory and the printing press. Regiomontanus remains famous for having built at Nuremberg the first astronomical observatory in Germany. In 1472 he published the first printed astronomical textbook, the "Theoricae novae Planetarum" of his teacher Georg von Peurbach. Peurbach worked at the Observatory of Oradea in Transylvania, the first in Europe, and established in his "Tabula Varadiensis" this Transylvanian town's observatory as laying on the prime meridian of Earth.

In 1475 he went to Rome to work with Pope Sixtus IV on calendar reform. On the way he could publish his "Ephemeris" in Venice. Regiomontanus died mysteriously in Rome, July 6, 1476, a month after his fortieth birthday. Some say he died of plague, others by (more likely) assassination.

A prolific author, Regiomontanus was internationally famous already in his lifetime. Despite having completed only a quarter of what he had intended to write, he left a substantial body of work. Domenico Maria Novara da Ferrara, the teacher of Nicolaus Copernicus, referred to Regiomontanus as having been his own teacher.

It is not true that he came to be called posthumously after the place of his birth, Königsberg/Bavaria (in Latin, Regiomontanus). In Regiomontanus' day it was common for scholars to Latinize their names when publishing.

He is known for having built one of the most famous automata, the wooden eagle of Regiomontanus, which flew from the city of Koenigsberg to meet the emperor, saluted him, and returned. He also built an iron fly of which it is said it flew out of Regiomontanus's hands at a feast, and taking a round, returned to him.

Regiomontanus and 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. 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 on Jamaica, to intimidate the natives into continuing to provision him and his crew from their scanty food stocks, when he successfully predicted a lunar eclipse for February 29, 1504.

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 either was as convinced of the validity and utility of astrology as his contemporaries, or was willing to set aside his misgivings for the sake of commercial success.

Short Biography profile and facts about the life of Regiomontanus
The following biography information provides basic facts and information about the life and history of Regiomontanus a famous Medieval character of the Middle Ages:

Nationality: German

Also Known as : Johann Muller

Lifespan: 1436 - 1476

Date of Birth: He was born on 6 June 1436 in Unfinden, near Königsberg), Germany

Family connections : He was the the son of a miller

Early Life and Education: Regiomontanus became a mathematical and astronomical prodigy at a very early age. His early education was at home

Career and Timeline of Regiomontanus :

1447 - 1450: Studied at the University of Leipzig

1450: Regiomontanus entered the University of Vienna and became a pupil of Peurbach

1457: Received his Masters degree

1457: He was appointed to the Arts Faculty of the University of Vienna where he worked on mathematics and astronomy

1457: Regiomontanus constructed instruments such as astrolabes

1461: Regiomontanus travelled to Rome with Cardinal Bessarion who was his patron

1463: Regiomontanus left Rome and travelled to Padua where he lectured at the university

1464: Regiomontanus wrote his book De triangulis omnimodis detailing methods for solving triangles

1467: Regiomontanus travelled to Hungary where his patron was the King of Hungary. He worked at the Royal Library in Budapest where he worked with Martin Bylica on astronomy and studied old manuscripts including Diophantus's Arithmetica

Regiomontanus completed the Epitome of the Alimagest which was begun by Peurbach

1471: Regiomontanus returned to Nurenburg where he built an observatory and constructed instruments such as the astrolabe, parallactic ruler, quadrants and Jacob's staff

1472: Regiomontanus set up a printing press in his own house and published various scientific and astrological works

In 1474 he published Ephemerides

Date of Death: Regiomontanus died on 6 July 1476 in Rome, Italy from the Black Death

Accomplishments or why Regiomontanus was famous: Regiomontanus made important contributions to mathematics, trigonometry and astronomy. His book Ephemerides was used by Christopher Columbus and Amerigo Vespucci to measure longitudes in their explorations of the New World.


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