Johannes Müller von Königsberg (6 June 1436 – 6 July 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 in the more famous East-Prussian Königsberg.
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 Almagest which Peurbach had begun at the initiative of Basilios 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 almagesti 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
