Famous Medieval Astrologers: Biographical Spotlights on Notable Figures

Introduction

Throughout the Middle Ages, as astrology permeated various facets of life, certain individuals stood out for their exceptional contributions to this celestial art.

From court astrologers who advised kings and queens to scholars who penned influential texts, these figures left an indelible mark on the trajectory of astrological thought.

This article shines a spotlight on some of the most iconic medieval astrologers and delves into their life stories, contributions, and enduring legacies.

Claudius Ptolemy (100-170 AD)

Life and Background

Claudius Ptolemy was an Egyptian astronomer, mathematician, and astrologer who lived in Alexandria. His work in the second century AD laid the foundations for Western astronomical and astrological practices for centuries to come.

Major Works and Contributions

Ptolemy’s “Tetrabiblos” is a seminal text in the field of astrology, presenting a comprehensive system that combines natural and judicial astrology. It has been the cornerstone of astrological teaching and practice, with its influence spanning across the medieval period into the Renaissance and beyond.

Legacy

Ptolemy’s work became the gold standard for astrological practice in the Western world. His approach to astrology as a part of a rational and natural order of the cosmos influenced not just astrologers but scholars in various fields of science and philosophy.

Guido Bonatti (c. 1223–1300)

Life and Background

As one of the most renowned astrologers of the 13th century, the Italian Guido Bonatti served at the courts of several Italian city-states. His services were not limited to casting horoscopes; he also advised on political and military strategies based on astrological readings.

Major Works and Contributions

Bonatti’s magnum opus, the “Liber Astronomiae” or “Book of Astronomy,” stands as a comprehensive treatise on medieval judicial astrology. Within its pages, he covers a range of topics from natal astrology to horary and electional astrology, providing insights, techniques, and examples for each.

Legacy

While facing criticism from religious quarters during his life, Bonatti’s influence persisted. His methods and techniques, especially in horary astrology, continue to resonate with astrologers today. His integration of Arabic astrological knowledge with Western thought solidified his position as a bridge between two rich traditions.

Abraham ibn Ezra (1089–1167)

Life and Background

Born in Tudela, Spain, Abraham ibn Ezra was a polymath excelling in various fields, including astrology, mathematics, and poetry. As a Jew in the Islamic Spain of his time, he was exposed to the rich tapestry of Andalusian knowledge, which greatly influenced his works.

Major Works and Contributions

Ibn Ezra penned numerous astrological treatises. Among them, “The Book of Reasons” critically examined the teachings of Ptolemy, while “The Book of Nativities” delved into natal astrology. He also wrote on electional and horary astrology, providing keen insights into each domain.

Legacy

As a conduit between Islamic and Christian worlds, ibn Ezra played a pivotal role in transmitting Arabic astrological knowledge to Europe. His commentaries and critical examinations of foundational texts provided fresh perspectives and remain influential in contemporary astrological studies.

John of Sacrobosco (c. 1195-1256)

Tractatus de Sphaera (Treatise on the Sphere)

Sacrobosco’s “Tractatus de Sphaera” was a foundational textbook on astronomy in the Middle Ages, widely used in European universities for centuries after its publication. It laid out the basic elements of the Ptolemaic system, which was the prevailing cosmological model that underpinned astrology.

Educational Influence

Because “Tractatus de Sphaera” was a standard educational text, Sacrobosco’s influence spread widely through the academic community, affecting the teaching of both astronomy and astrology. His works helped to standardize and disseminate astrological knowledge within the framework of medieval education.

Legacy

Sacrobosco’s influence endured well into the Renaissance, making him a key figure in the transmission of astronomical and astrological knowledge from the classical world to the later medieval and early modern periods.

Roger of Hereford (fl. 1176)

Life and Background

Roger of Hereford was an English astrologer and cleric who lived in the 12th century. His work is indicative of the period’s intellectual climate in England, where astrology was pursued in conjunction with other scientific inquiries.

Major Works and Contributions

His translations from Arabic texts and original compositions on astrology contributed significantly to the dissemination of astrological knowledge in medieval England. His work helped to integrate the advanced Arabic astrological science into the Western tradition.

Legacy

Roger’s contributions helped establish astrology as a respected science in medieval England, influencing the curriculum of educational institutions and the practices of later astrologers.

Hermes Trismegistus

Life and Background

Hermes Trismegistus is a legendary Hellenistic figure, often identified with the Greek god Hermes and the Egyptian god Thoth. He is reputed to be the author of the Hermetic Corpus, a series of texts that are the foundation of Hermeticism.

Major Works and Contributions

The Hermetic texts, particularly those concerned with astrology, have played a crucial role in the development of Western esoteric traditions. These writings address the influence of the stars on the earthly realm and the use of astrology for spiritual ascension.

Legacy

The philosophy attributed to Hermes Trismegistus has had a profound and enduring influence on Western mystical thought, including Renaissance thinkers who sought to reconcile Hermeticism with Christianity.

Geoffrey Chaucer (c. 1343-1400)

Life and Background

Geoffrey Chaucer, known as the Father of English literature, was also a philosopher, diplomat, and astronomer. He is best known for his literary masterpiece, “The Canterbury Tales.”

Major Works and Contributions

Chaucer’s “Treatise on the Astrolabe” is a didactic work that introduces the use of the astrolabe to a lay audience. It’s one of the earliest technical manuals in English and demonstrates the practical applications of astrology in daily life.

Legacy

While Chaucer’s literary works overshadow his contributions to astrology, his “Treatise on the Astrolabe” highlights the importance of astrology and astronomical instruments in medieval society and has historical significance as a document of practical science.

Albertus Magnus (c. 1200-1280)

Life and Background

Albertus Magnus, also known as Saint Albert the Great, was a German Dominican friar and bishop who became famous for his comprehensive knowledge of the natural sciences, philosophy, and theology.

Major Works and Contributions

Albertus Magnus wrote extensively on a variety of scientific and philosophical topics. In the realm of astrology, he explored its relationship with the natural world and the philosophical implications of celestial influences on earthly affairs.

Legacy

Albert’s works bridged the gap between faith and reason, laying the groundwork for later medieval scholars. His writings on astrology helped to contextualize it within the broader scope of natural philosophy and science.

Lesser-Known Contributors to Medieval Astrology:

1. Roger Bacon (c. 1214-1294):
   • Contribution: An English philosopher and Franciscan friar who wrote on a variety of scientific subjects, including astrology.
2. Michael Scot (c. 1175-c. 1232):
   • Contribution: His translations of Arabic astrological texts into Latin helped spread astrological knowledge throughout Europe.
3. Dante Alighieri (1265-1321):
   • Contribution: While primarily known for his literary work, Dante’s “Divine Comedy” contains many references to the cosmology and astrology of his time.
4. Johannes de Sacrobosco (John of Holywood):
   • Contribution: Not to be confused with John of Sacrobosco mentioned above, he was another medieval scholar who wrote on astronomy and astrology.
5. Richard of Wallingford (1292-1336):
   • Contribution: An English abbot and mathematician, he designed an astronomical clock and wrote on astrology and its computations.
6. Levi ben Gerson (Gersonides) (1288-1344):
   • Contribution: A Jewish philosopher, he wrote “The Wars of the Lord” which includes discussions on astrology and astronomy.
7. Nicole Oresme (c. 1320-1382):
   • Contribution: A philosopher who wrote on a variety of scientific topics and critiqued some of the astrological practices of his time.
8. William of Conches (c. 1090-c. 1154):
   • Contribution: His philosophical works discussed the influence of stars on the sublunar world, which was a common theme in medieval astrology.
9. Cecco d’Ascoli (1257-1327):
   • Contribution: An Italian astrologer and physician who wrote “Acerba,” a poem that incorporates astrological themes and was condemned for heresy.
10. John Gower (c. 1330-1408):
    • Contribution: A contemporary of Chaucer, his poetry often referenced astrological concepts.

These figures, among others, carried the tradition of astrological study and practice forward throughout the medieval period in Europe, adapting and integrating a mix of inherited wisdom and contemporary scholarship. Each contributed to the preservation and development of astrology, influencing the direction it would take in subsequent centuries.