Astrology in the Renaissance court
A university discipline, a court appointment, and the same people doing the astronomy.
3 min read · Published 2 September 2026
The short answer
In Renaissance Europe astrology was taught in universities, practised at courts, and integrated into medicine. Court astrologers advised on timing for military and political decisions, physicians consulted charts before treatment, and the same individuals frequently produced significant astronomical work. The separation of astronomy from astrology is a later development, not a feature of the period.
It was a profession
Astrology was taught within the university curriculum, frequently alongside medicine, and a physician's training could include chart interpretation.
Courts employed astrologers, and the work was practical: electional advice on when to undertake something, horary answers to specific questions, natal readings for royal children, and medical astrology.
This was not a fringe activity tolerated at the margins. It was an established professional discipline with institutional standing, and treating it as embarrassing superstition misdescribes how it functioned at the time.
The astronomers were the astrologers
This is the point most often missed, and it matters for how the history is read.
Kepler cast horoscopes professionally and it formed part of his income. He was also sharply critical of much astrological practice while defending a version of it.
Tycho Brahe produced astrological work alongside the observational programme that made Kepler's laws possible.
Galileo cast charts, including for family members and patrons.
The reason is straightforward: casting a chart requires accurate planetary positions, so demand for astrology funded the observational and computational work that produced modern astronomy. The same relationship operated in the Islamic world and in Indian astronomy.
That is a historical fact about motivation and funding. It is not evidence that the astrology worked, and it is sometimes deployed as though it were.
Why it declined
- Heliocentrism undermined the physical picture astrology's causal claims relied on, though the symbolic version survived it.
- Newtonian mechanics provided a mechanism for celestial motion that made planetary influence on human affairs harder to state coherently.
- Institutional separation. As astronomy professionalised, it distinguished itself from astrology, and the two ceased to be one activity.
- Medicine changed. Testable methods displaced humoral and astrological frameworks, removing astrology's most practical application.
- The Enlightenment shift in what counted as knowledge left astrology outside the boundary.
Notice that no single refutation occurred. Astrology was not disproved and then abandoned; it lost institutional standing across two centuries as the surrounding framework changed. That is the more accurate account, and it explains why it persisted culturally after losing academic status.
What survives from that period
William Lilly's Christian Astrology of 1647 is the major English-language source and remains the reference for horary practice — see the best books.
The traditional technique revived over recent decades draws on this material as well as on Hellenistic sources.
And the vocabulary persists in ordinary English: 'disaster' from *dis-astro*, ill-starred; 'influenza' from an Italian term for celestial influence; 'jovial', 'saturnine', 'mercurial' and 'lunatic' all from planetary associations. The framework left its fingerprints on the language long after leaving the universities.
Common questions
- Was astrology taken seriously in the Renaissance?
- Yes. It was taught in universities, frequently alongside medicine, practised professionally at courts, and integrated into medical treatment. It was an established discipline with institutional standing rather than a fringe activity.
- Did famous astronomers practise astrology?
- Yes. Kepler cast horoscopes professionally as part of his income, Tycho Brahe produced astrological work alongside his observations, and Galileo cast charts. Demand for astrology funded the observational work that produced modern astronomy.
- Why did astrology decline?
- Gradually rather than through refutation. Heliocentrism and Newtonian mechanics undermined its causal picture, astronomy professionalised separately, medicine adopted testable methods, and Enlightenment standards of knowledge left it outside the boundary.
- Which English words come from astrology?
- Several. 'Disaster' derives from terms meaning ill-starred, 'influenza' from an Italian word for celestial influence, and 'jovial', 'saturnine', 'mercurial' and 'lunatic' all come from planetary associations.