# Regiomontanus

> German mathematician and astronomer (1436–1476)

**Wikidata**: [Q76365](https://www.wikidata.org/wiki/Q76365)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Regiomontanus)  
**Source**: https://4ort.xyz/entity/regiomontanus

## Summary
Johannes Regiomontanus was a German mathematician and astronomer renowned for his contributions to astronomy and mathematics during the 15th century. Born in 1436, he played a pivotal role in advancing trigonometry and astronomical observation, notably through his work *De triangulis omnimodis* (On All Kinds of Triangles). His efforts laid foundational principles for later scientific advancements.

## Biography
- **Born:** June 6, 1436, in Königsberg, Holy Roman Empire (modern-day Germany)
- **Nationality:** German
- **Education:** Studied at the University of Leipzig and the University of Vienna
- **Known for:** Pioneering work in trigonometry, astronomy, and early printing of scientific texts
- **Employer(s):** University of Vienna, Holy Roman Emperor Frederick III
- **Field(s):** Mathematics, Astronomy, Astrology

## Contributions
- **De triangulis omnimodis (1464):** A comprehensive treatise on trigonometry that systematized the field and influenced later mathematicians.
- **Astronomical Almanacs:** Produced detailed almanacs for the years 1474–1476, which included planetary positions and weather predictions.
- **Printing Innovations:** Established a printing press in Nuremberg, publishing works such as Ptolemy’s *Almagest* and his own *Ephemerides*, which facilitated the dissemination of astronomical knowledge.
- **Regiomontanus' Angle Maximization Problem:** Formulated a mathematical optimization problem that remains a classic in geometry.

## FAQs
### Q: What were Regiomontanus' major mathematical contributions?
**A:** He authored *De triangulis omnimodis*, a foundational text in trigonometry, and formulated the angle maximization problem, a significant geometric challenge.

### Q: How did Regiomontanus influence astronomy?
**A:** His *Ephemerides* provided accurate planetary tables, aiding celestial navigation and observational astronomy. He also promoted the use of the Alfonsine Tables and advocated for observational rigor.

### Q: Where did Regiomontanus work?
**A:** He was associated with the University of Vienna, collaborated with Holy Roman Emperor Frederick III, and operated a printing press in Nuremberg.

### Q: What legacy does Regiomontanus hold in science?
**A:** His works were instrumental in the development of modern trigonometry and astronomy, directly influencing later scientists such as Copernicus and Kepler.

## Why They Matter
Regiomontanus bridged medieval and Renaissance science, revitalizing interest in classical texts while advancing original research. His trigonometric work enabled more precise astronomical calculations, critical for navigation and cosmology. By establishing a printing press, he democratized access to scientific knowledge, accelerating the spread of ideas during the Scientific Revolution. Without his contributions, the development of modern astronomy and mathematics would have lacked key methodological and textual foundations.

## Notable For
- **First Printed Astronomical Almanac:** Published *Ephemerides* (1474), the first printed astronomical almanac.
- **Revival of Trigonometry:** Systematized trigonometric principles in *De triangulis omnimodis*.
- **Printing Press Pioneer:** Used early printing technology to disseminate scientific works, enhancing scholarly communication.
- **Influence on Copernicus and Kepler:** His emphasis on observational accuracy and mathematical rigor shaped later astronomical breakthroughs.

## Body

### Early Life and Education
Born on June 6, 1436, in Königsberg, Regiomontanus studied at the University of Leipzig (1451) and later at the University of Vienna (1453), where he deepened his expertise in mathematics and astronomy under the tutelage of Georg von Peuerbach.

### Career and Major Works
- **Collaboration with Peuerbach:** Assisted his mentor in preparing a new translation of Ptolemy’s *Almagest*, fostering engagement with classical astronomy.
- **Trigonometric Innovations:** Authored *De triangulis omnimodis* (1464), which organized trigonometric knowledge and introduced novel methods for solving triangles.
- **Astronomical Observations:** Conducted systematic observations of the heavens, including the comet of 1472, and critiqued astrological practices while emphasizing empirical observation.
- **Printing Press Ventures:** Established a press in Nuremberg, publishing critical editions of classical texts and his own works, such as *Ephemerides* (1474), which provided planetary positions for 1474–1476.

### Legacy and Influence
Regiomontanus’ works were instrumental in the education of later astronomers, including Nicolaus Copernicus, who referenced his tables and methods. His integration of mathematical rigor with observational astronomy set a precedent for the Scientific Revolution. The *Regiomontanus’ angle maximization problem* remains a notable challenge in geometry, reflecting his enduring impact on mathematical thought.

### Commemoration
His contributions are honored through the lunar crater Regiomontanus and the asteroid 9307 Regiomontanus, underscoring his significance in the history of science. Institutions such as the University of Vienna and Leipzig University recognize his role as a pivotal figure in the advancement of mathematics and astronomy.

## References

1. [Müller (Johann). Zedler, Großes vollständiges Universallexicon aller Wissenschaften und Künste. 1739](http://www.zedler-lexikon.de/blaettern/zedlerband.html?action=blaettern)
2. [Müller (Regiomontanus), Johann. The Catholic Encyclopedia. 1913](https://archive.org/stream/catholicencyclop10herbuoft?ui=embed#page/628/mode/1up)
3. Integrated Authority File
4. A Short History of Astronomy
5. Great Soviet Encyclopedia (1969–1978)
6. Virtual International Authority File
7. BnF authorities
8. MacTutor History of Mathematics archive
9. Czech National Authority Database
10. Mathematics Genealogy Project
11. International Standard Name Identifier
12. CiNii Research
13. Campo Santo Teutonico
14. Freebase Data Dumps. 2013
15. [Source](https://www.nuremberg.museum/artist/show/287-regiomontanus-mueller-johannes)
16. [Source](http://digitale.beic.it/primo_library/libweb/action/search.do?fn=search&vid=BEIC&vl%283134987UI0%29=creator&vl%28freeText0%29=Regiomontanus%20Johannes)
17. CERL Thesaurus
18. LIBRIS. 2018
19. Bibliography of the History of the Czech Lands
20. Provenio
21. HMML Authority File
22. Digital Scriptorium Catalog