review of individual chapters. In it he wrote: 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. 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. Much of the material on spherical trigonometry in Regiomontanus' On Triangles was taken directly from the twelfth-century work of Jabir ibn Aflah otherwise known as Geber, as noted in the sixteenth century by Gerolamo Cardano. Publications Legacy Simon Stevin, in his book describing decimal representation of fractions (De Thiende), cites the trigonometric tables of Regiomontanus as suggestive of positional notation. Regiomontanus designed his own astrological house system, which became one of the most popular systems in Europe. 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. There is an image of him in Hartmann Schedel's 1493 Nuremberg Chronicle. He is holding an astrolabe. Yet, although there are thirteen illustrations of comets in the Chronicle (from 471 to 1472), they are stylized, rather than representing the actual objects. The crater Regiomontanus on the Moon is named after him. See also List of unsolved deaths Regiomontanus' angle maximization problem Notes References Further reading 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, Helmuth Gericke: Mathematik im Abendland: Von den römischen Feldmessern bis zu Descartes. Springer-Verlag, Berlin 1990, Günther Harmann (Hrsg.): Regiomontanus-Studien. (= Österreichische Akademie