Astrology was widely used by medical practitioners to understand both the nature and likely prognosis of disease. The constellations were thought to rule over different parts of the body and cause different illnesses. So while Scorpio ruled the reproductive system, Aries governed the head. Similarly, Saturn under Taurus encouraged scrofula (a swelling of the neck caused by tuberculosis), otherwise called ‘The King’s Evil’.

Allmanach auff das 1581 jar ... 

by Petrus Slovacius, Wroclaw, 1580

Illustration showing the ruling constellations of the different body parts. The different astrological signs were also associated with the different temperaments. Aries, Taurus and Gemini were sanguine; Aquarius, Capricorn and Pisces were phlegmatic; Scorpio, Sagittarius and Libra were melancholic; Cancer, Leo and Virgo were choleric.

Image courtesy of the Wellcome Library, London, England