How astrologers practiced early medicine

Lauren Kassell, Chair in History of Science at the European University Institute, explains historical links between astrology and medicine.
Lauren Kassell

Chair in History of Science

13 Oct 2021
Lauren Kassell
Key Points
  • Records written by a pair of astrologer physicians in the late 16th and early 17th century chronicle tens of thousands of cases with details about patients’ lives and the kinds of questions they wanted answers to.
  • Astrologers were trying to be part of the learned tradition of medicine founded in antiquity, following the teachings of Hippocrates, that were systematised by Galen into what was called humoral medicine.
  • Astrologers at the time based their analysis on how celestial bodies were positioned at particular moments in time and tried to balance the four humours in the body: blood, phlegm, bile and black bile.

Bound volumes of astrologer physicians

There’s a run of more than 60 large leather-bound volumes in the Bodleian Library in Oxford, which contain day-by-day records written by a pair of astrologer physicians that start around 1596 and end around 1634. These records contain 80,000 written consultations trying to figure out the answer to a question that a patient or a client asked the astrologers. The answer to the question depended on the moment that the question was asked.

Entrance to the Bodleian Library School of Metaphysics, University of Oxford. Photo by Walid Nohra.

Chronicles of questions

The astrologers worked with a system. They began by writing down the person’s name at the top, and then they wrote their age, whether or not they were married, particularly in cases of women, sometimes their address, sometimes other information about them, and then the question that they wanted the answer to. Usually, the question was something like, what is my disease? Am I pregnant? Sometimes the question was a little bit more elaborate, like: I’ve had fevers on and off for three weeks. What is wrong with me?

This is why we think these records survive, or why these records were written as records, because doctors didn’t necessarily work with a pen in hand. The astrologers would then draw what we would think of as a horoscope. They would draw a chart, which was a map of the heavens at the moment that the question was asked. These astrologers practised a kind of astrology called horary astrology, which is dependent on the time that somebody does something. It’s a little bit like fortune-telling. They then, based on their expertise at reading this chart, would come up with a judgement which they might or might not share in full with the patient. They would then also, in many cases, recommend a treatment, and sometimes they would record, but not always, whether or not they were paid for these services.

These records are preserved for reasons that we don’t fully understand, but they document this day-by-day activity of these two practitioners, Simon Foreman and his student, Richard Napier. Their records give us this extremely rich and unusual account of what was going on with the 65,000 individuals who appear in their records.

Humoral medicine

When the astrologers judged (that’s their word for it), when they judged the position of the celestial bodies at a particular moment in order to answer a question, they were negotiating their understanding of the way the human body – their patients’ bodies – worked. Now, we know what the astrologers thought about how human bodies worked because they read texts. They were trying to be part of the learned tradition of medicine founded in antiquity, following the teachings of Hippocrates, that were systematised by Galen into what was called humoral medicine.

Humoral medicine was about balancing the four humours in the body. Each humour was tied to a combination of the four Aristotelian elements. The Aristotelian elements are hot, cold, moist and dry, and the four humours are blood, phlegm, bile and black bile, which is also melancholy. In this Aristotelian universe, which is the universe that the astrologers inhabited, each of the stars and planets were also constituted by these elements – the hot, cold, moist and dry.

Diagnosis and prediction

Photo by Vera Petruk.

What the astrologers were doing was judging the set of correspondences within their horoscope and diagram – what they were being told. So, if a particular planet was in a particular house, then that might indicate a malady of the head. It might also, if a hot planet or a dry planet were in a particular area, signify a fever. The astrologers were making sense of all of this in relation to what the patient was telling them and other aspects of the case that they might observe, and then their treatments would partake of the same set of correspondences.

If somebody had a superfluity of blood – the blood is hot and wet – then they would need to let blood evacuate some of the foul humours that were within their body. All sorts of other forms of evacuation were used, upwards or downwards, as was the euphemism they used. There was also a tremendous regard for the way that the body knew how to balance itself. In this world, all bodies are individual; we are not yet in the era where there is a normative template, where things are being quantified and where all bodies are expected to be the same.

Natural forms of evacuation

If, for instance, in some of the most extraordinary cases, a man bled from his haemorrhoids regularly, there was no imperative – there was a whole theoretical set of discussions about this, not by astrologers, but by other people – to let them continue, because that was their body finding a natural form of evacuation in the same way a healthy woman would menstruate regularly (not that all women menstruated according to the same regime, but rather each woman to her own system of evacuation). So, the astrologers tapping into this long-standing, extremely elaborate form of medicine – which we do an injustice to when we say it was just humoral medicine as it’s a set of correspondences – have a huge set of theories and set of expertise that underpins this. Even those of us who read their texts are only really beginning to understand that they used these methods to work with people within their ordinary regimes. This is what doctors do. They counsel on regimes to help to return somebody to health, and once they are healthy, they help them to maintain their health.

Types of questions and problems

All sorts of people with all sorts of problems came to the astrologers. Sometimes, it’s been argued, they were specialists in gynaecological complaints. It was hard to know whether you were pregnant in this era, but they had plenty of ways of knowing. That’s an example of one of the regular questions. It’s also argued that they specialised in cases of madness, particularly Richard Napier, who was also a clergyman.

Writing day after day

The fact that the astrologer physicians wrote their consultations day by day, year by year, tells us it’s a moment in history. It shows us that this is a point at the beginning of doctors starting to record cases like this. Hippocrates had allegedly recorded cases on animal skins. Cases creep into subsequent writings by doctors, usually as marginal examples, because theory is what was the mainstay of rational medicine, but in some, from around the 1550s, doctors begin to say, actually, you should write that down. The doctors that are training new doctors say, you should write down your cases.

This is also when we have account keeping, whether accounts of merchants or accounts of one’s own life, in the form of what becomes autobiography: these accounts in the eyes of God.

Hippocratic bust. Photo by Ammatar.

Process of systematising

The astrologer physicians partake in a series of traditions where writing day by day what some people might think of as trivia is part and parcel of how people work. Here, we have a kind of antecedent that helps us to show the way natural inquiry and medical understanding is made from particulars. The records I’ve worked on aren’t part of the long history of medical cases. Nobody went back and said, ‘I’m going to re-examine these cases’ or ‘I’m going to use these cases to build the science of medicine’, but they are an instance of the ways in which encounters took place and the ways in which the process of systematising that encounter and documenting it day by day was integral to the healing experience.

Discover more about

how astrology and medicine were connected

Kassell, L. (2018). Fruitful Bodies and Astrological Medicine. In: N. Hopwood, R. Flemming, & L. Kassell (Eds.), Reproduction: Antiquity to the Present Day. Cambridge University Press.

Kassell, L. (2014). Casebooks in Early Modern England: Medicine, Astrology, and Written Records. Bulletin of the History of Medicine, 88(4), 595–625.

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