Johannes Müller von Königsberg, today best known by the Latin epithet Regiomontanus, was a German mathematician, astronomer, astrologer, translator, instrument maker and Catholic bishop.
He was also known as Johannes der Königsberger (Johannes of Königsberg). His writings were published under the name of Joannes de Monte Regio, a Latinized version of his name. Both names mean "John of King's Mountain". The name "Regiomontanus" was first coined by Philipp Melanchthon in 1534, fifty-eight years after Regiomontanus' death.
Regiomontanus was born in 1436 and died in 1476. A small, only 20 mm in diameter brass medal was issued by the city Königsberg for 500th anniversary of his death in 1976. On the obverse we can find his portrait facing half left, his name and his death year along with the issue year. On the revers the coat of arms of the city with its name is displayed.
The short life of Regiomontanus was full of travels. At eleven years of age, Regiomontanus 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 Peuerbach. In 1452 he graduated with a BA and was awarded his “magister artium” (Master of Arts) at the age of 21 in 1457. It is known that he held lectures in optics and ancient literature.
In 1460 the papal legate Basilios Bessarion came to Vienna on a diplomatic mission. Being a humanist scholar and great fan of the mathematical sciences, Bessarion sought out Peuerbach's company. In 1461 Regiomontanus left Vienna with Bessarion and spent the next four years traveling 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. In 1465, he built a portable sundial for Pope Paul II.
He went to work for János Vitéz, archbishop of Esztergom in 1467. He built and furnished an observatory and workroom there with constellations painted on the ceiling. The remains of this ceiling depicting the Zodiac was found during the excavations. There he calculated extensive astronomical tables and built astronomical instruments. Later he went to Buda, and spent the next three years in Hungary under King Matthias Corvinus as custodian of the library abundant with treasures from Constantinople and Athens. The ensuing Bohemian wars of the king, however, led Müller to look for a quiet place where he could carry out his work, and he decided upon Nürnberg, then the center of industry, intellect and commerce in southern Germany.
The observatory at Nuremberg was established by Regimontanus, who wrote in a letter to a friend on 4 July 1471: "Quite recently I have made observations in the city of Nürnberg... 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 center of Europe because of the journeys of merchants."
This date was used for issuing a small, 26 mm diameter commemorative silver medal in 1971 for the 500th anniversary of the observatory. On the obverse the portrait of the founder, Regiomontanus, or Johannes Müller von Königsberg, is displayed in half left face view. On the left side is his year of birth 1436, on the right his death 1476. Legend above is his name in original and Latin form: "JOHANNES MÜLLER • REGIOMONTANUS", below: " • ASTRONOM UND MATHEMATIKER •", i. e. astronomer and mathematician. On his shoulder the purity of silver (986) from which this medal was made is marked.
On the reverse the observatory dominates the scene in its current form. This observatory has been standing for over 70 years at the Rechenberg, and has nothing else common with the original small and private observation site that Regiomontanus built than its name. The observatory of Nuremberg is called Regiomontanus Observatory (Regiomontanus Sternwarte). Legend around is:"1471 ERRICHTET REGIOMONTANUS I. DEUTSCHE STERNWARTE", i. e. 1471 built Regiomontanus the first German observatory. In the inner circle and above the building is: "STERNWARTE NÜRNBERG", "500 JAHRE", i. e. Nurenberg Observatory 500 years. The purity of silver (986) is marked on this side too below the building.
In 1475 he was called to Rome to work with Pope Sixtus IV on calendar reform. Regiomontanus died of unknown causes in Rome, July 6, 1476, and the calendar reform was postponed by more than a century.