Medicine, the sky, and the rhythms of creation: Thoughts on natural astrology
For much of history, the study of stars was a science, not a mystical art. The same doctors who cared for the sick and studied anatomy also charted the movements of the moon and planets. For medieval physicians, the heavens and bodies were woven into one grand pattern of divine design. Understanding the pattern was seen as an act of respect for the Creator, not rebellion against it.
Doctor as Astrologer
At the great universities of the Middle Ages, Paris, Bologna, and Oxford, medical students studied both astronomy and astrology. Astronomy refers to the measurements and geometry of the heavens, such as the movement of the moon, how solar eclipses work, and how calendars are calculated. Astrology meant understanding how the rhythms of the heavens affect life on Earth: the weather, crops, tides, and the human body.
It was believed that the body itself reflected the universe. Medieval manuscripts often depict a “zodiacal man” mapped from head to foot with the 12 constellations. Aries rules the head, Taurus the neck, Leo the heart, and Pisces the feet.
The passage of the moon through these signs guided doctors in the timing of treatment. They believed that when the moon passes through a sign that rules a certain part of the body, that part becomes more “sensitive.” Therefore, surgery and bloodletting were considered best avoided at that time.
This was not a superstition for them, but a science, an attempt to cooperate with the rhythms of nature rather than against them. Their moon phase and constellation calendars were health tools, much like stethoscopes are today.
Zodiac Man and Phlebotomy Man combine to show you when and where to perform bloodletting. From John Foxton’s Liber Cosmographiae, 1408.
The moon and the natural order
In particular, the moon held a special place in medicine. Its phase was thought to affect the body’s fluids in the same way it affects the tides. Physicians used the lunar calendar to record important dates of illness and recovery. Even Christian scholars like Thomas Aquinas acknowledged that the heavens could influence things in nature, such as the weather, the seasons, and even the temperament of the body, but argued that the stars could not control human souls or wills.
Thus, medieval “astrology” was not fortune-telling, but a form of natural philosophy, the study of the order of creation under God.
faith, science and symbolism
As a recent convert to Catholicism, I find this historical perspective deeply moving. It is a reminder that faith and science were never antagonists. Medieval physicians looked at the stars and saw not a force to be feared, but a language in which God revealed His order and harmony.
My own interest in the moon and the zodiac follows a similar path. It’s not fortune-telling, it’s contemplation. I no longer write “predictions” or predictions. Instead, I use the lunar cycle as an opportunity to think about health, rhythm, and balance. Full and new moons are natural indicators of time. It is a moment to stop, breathe, and notice how creation itself moves in cycles of light and rest.
Upcoming: Month as a teacher of balance
In the 2026 Moon Report, I will focus on what I call natural astrology: looking at the relationships between the heavens and the natural world without giving them the power to control your destiny. Each full moon will reflect the rhythms of your life: when to slow down, when to act, when to rest, and when to create.
We’ll also talk about how ancient and medieval healers used the timing of the moon, not as medical advice, but as insight into how people once tried to live in harmony with the natural world. My hope is to combine science, spirituality, and history to show how moonlight can guide consciousness rather than predicting it.
Psalm 19 declares: “The heavens proclaim the glory of God, and the heavens proclaim the work of God’s hands.” That passage captures the essence of this work. The moon and stars are not omens, but reflect the natural rhythms of life and the deep connection between our bodies and the elements. They remind us that even as we draw closer to God, we belong to the wonders of the natural world.
Featured images; “Blood Moon” by Marina Marchionne Heavenly & Holy on Etsy
Source: Darkstar Mythology – darkstarastrology.com
