Passion of the People – 1.1.8

Middle Ages Belief in the Power of Stars

In the medieval world, from about 500 to 1500, astronomy was a required field of study. Universities across Europe organized their courses and bookshelves around the seven liberal arts: grammar, rhetoric, logic, music, geometry, arithmetic, and astronomy. In the centuries of the migration of people, Central and Western Europe had largely lost contact with ancient Greco-Roman cultural knowledge. Only in the Greek-speaking Byzantine Empire did ancient astronomical literature remain accessible and studied. In the Latin-speaking West, on the other hand, very little of this tradition was available until the 12th century. 

From London to Baghdad and beyond, students of medicine, philosophy, and even theology carefully observed the astrological relationship between the 12 signs of the zodiac and one’s physical, mental, and spiritual well-being. Indeed, peoples of many religions believed that the radiant Sun, full Moon, twinkling stars, and distant planets held great power over their lives, the seasons, and daily activities. Stargazing influenced everyday decisions in the Middle Ages. 

The work of astronomers in the Middle Ages consisted mainly of the transmission, translation and improvement of ancient astronomical writings. Western European scholars adopted the astronomical theories of Ptolemy from the Arabs. Ptolemy had taught that the Earth was a sphere in the centre of the world and that the Sun and all the stars orbited it. 

Islamic astronomers were the leaders in this field. The leading Islamic scientists were often also court astronomers or court mathematicians. The Arab achievements were mainly in the field of astrometry:

  • accurate observations of the sky – also for astrological purposes, although Islam disliked the attempted look into the future and did not permit astrology;
  • creation of star catalogues, naming of bright stars (still in use today);
  • further development of the astrolabe and precise measurement of the ecliptic slant.

The medieval scholars adopted from the Arabs the teaching that the planets influenced the fate of human beings through their position in the sky. They tried to predict the future from the position of the planets. This fortune-telling developed into an entire system that came to be called “astrology”. However, major innovations were largely absent at this time.

Arabic Astrolabicum, beginning 13th century
Gregor Reisch: Margarita Philosophica, 1503. Allegory “Astronomia”

Further Resources

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Chart showing signs of the zodiac and the solar system with the world at centre (Andreas Cellarius Harmonia Macrocosmica, 1660/61)

Astrolabio – Getty Images


Medieval astronomy

Astronomers From The Medieval Islamic World (History videos)

Islamic Contributions to Astronomy and Navigation

Astrology in the early Islamicate World

Ancient Astronomy to the Middle Ages

Astronomia e astrologia nel Medioevo – ERID LAB

Astrometria – Polimi OpenKnowledge

Online Resources

Written in the Stars: Astronomy and Astrology in Medieval Manuscripts (a blog post about how faith, science, and stargazing influenced everyday decisions in the Middle Ages)

Medieval astrology guide about the ancient practice of astrology

Astronomical Instruments in the Middle Ages: More than just a timepiece

Astronomical Knowledge in the Sacred Architecture of the Middle Ages in Italy (Manuela Incerti)

The Idea of the ‘Dark Ages’ Is a Myth. Here’s Why Medieval Scientific Progress Still Matters

Astrology and Medicine in Medieval Times

Astrolabes in Medieval Jewish Culture (a project by Warburg Institute and Oxford University)

Medioevo: la scienza siriaca. Matematica e astronomia – TRECCANI

Le arti liberali nel Medioevo – Stefano Torselli, Goticomania

La civiltà islamica: osservazioni, calcolo e modelli in astronomia. L’astronomia araba nella tradizione medievale latina – TRECCANI

I cieli dell’IslamIstituto e Museo di Storia della Scienza, Museo Galileo

Astrolabio – Articoli di astronomia

L’astrolabio di Verona svela un antico dialogo scientifico tra i popoli del Mediterraneo – Focus

Astrometria – Polimi OpenKnowledge

Further Readings

Astrology and Medicine in Later Medieval England. The Calendars of John Somer and Nicholas of Lynn (Paper by Cornelius O’Boile)

Astronomy and Astrology in the Medieval Islamic World (Edward. S. Kennedy. 1998)

Early-Medieval Cosmology, Astronomy, and Mathematics (in: The Cambridge History of Science)

L’Età dei Lumi: astronomia. L’astronomia stellare – TRECCANI

Teaching Material

Course on Cultural Astronomy and Astrology (University of Wales)

Medieval Astronomy in the Middle Ages

How to read a medieval astronomical calendar (by Seb Falk)

L’astronomia nel Medioevo – Unibo

La storia dell’astronomia – I Libretti di Gaia

For Kids

A tutorial for secondary school pupils aged from 15 years up

Astronomiedidaktik, Unterrichtsmaterial

L’astrolabio – La scienza di Ido