Astrology, plague, and prognostication in early modern England: A forgotten chapter in the history of public health

The ability to foresee the outbreak of epidemic disease, and to predict its course, is a highly coveted skill. Most often associated with statistical techniques, such efforts to improve the health of communities are thought to be exclusively modern. Public health more generally is often said to be categorically distinct from pre-modern medicine, which was interested above all in individual patients and rarely considered the broader health of a population. This article challenges these long-entrenched views by showcasing early modern astrologers at work on disease at the population level. Located at the intersection of medicine and mathematics, astrology was once a promising methodology for monitoring the health of the people. Astrologers made annual predictions about the diseases that would predominate in particular regions, disseminating their forecasts widely alongside advice on what should be done in response. Their ability to think in terms of relatively standardized ‘populations’ — alongside their attempts to correlate the incidence of disease with external factors — made astrologers prime candidates for developing novel approaches to epidemics. Before the epidemiologist there was the astrologer, who looked to the stars to find patterns between celestial configurations and major health events, using their findings to model the rise and fall of epidemics.