Regiomontanus bigraphy, stories - German astronomer, astrologer, and mathematician

Regiomontanus : biography

June 6, 1436 – July 6, 1476

Johannes Müller von Königsberg (6 June 1436 – 6 July 1476), today best known by the Latin epithet 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 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 Phillip Melanchthon in 1534, fifty-eight years after Regiomontanus’ death.


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 abridgement 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. 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.