Medical Astrology: Science, Art, and Influence in early-modern Europe

General Medicine, Precisely Timed: Calendars

Explore: A Medical Astrologer’s Calendar | Popular Prognostication: A Farmers Almanac | Diagnostic Diagrams: Assessing Seasonal Influence | Under the Weather

A Medical Astrologer’s Calendar

Detail of the "Semi-Diameters of the Moon and Lunar Eclipse Shadow" volvelle. Astronomicum Caesareum (1540). Click the image for more.

Annual broadsheet calendars, like the one pictured below, were an important source for astrological information in the sixteenth century. Accessible, affordable, and popular, they were a common sight in homes and market squares across the Holy Roman Empire. They were also an indispensable tool for the general practice of medical astrology, providing prognostications primarily based on the movements of the Moon and Sun. A range of authors were responsible for these predictions, including astrologically trained physicians and astronomers, like Peter Apian (1495–1552). Historians Anthony Grafton and Darin Hayton explain that printing accurate wall-calendar predictions was a way to display expertise and build up a local reputation. An example of this convention is seen in the document below, which clearly names a particular person: Johannes Rüss, Medical Doctor in Konstanz (Germany). Printed in 1519, this red-and-black-ink calendar is one of two known exemplars associated with Rüss’s medical practice—the other is from 1512 and was printed by Michael Furter (d.1516–17) in Basel. However, little else is known about Rüss or his practice. The calendar itself helps fill in some gaps, though its information is likewise only partial.

Johannes Rüss, M.D., Calendar for the Year 1519. Click the image for more information.

That a second sheet is missing is made clear by the red headings on the page, which name only six months in the solar year: January [Jenner], February [Hornung], May [Mey], June [Bachmon], September [Herbstmonat], and October [Weinmonat]. Above this, several symbols are also missing from the glossary at right, though much information still remains. Notice, for example, the figures along the top. The Zodiac Man at center points to a lunar-based physic, while the figures on either side evoke a more advanced level of medical expertise. These figures are Saints Cosmas and Damian. The patron saints of pharmacy and medicine, Cosmas and Damian were twin brothers and physicians, who lived during the 3rd century in what is now modern-day Syria, where they treated and operated on patients without fee. Martyred under the reign of the Roman Emperor Diocletian (284–305 CE), the two physician-Saints are here portrayed with the tools of their earthly trade: the urine bottle and the medicine box, with spoon for administering medicine. More than mere decoration, these figures again stress Rüss’s stated university credentials: he was a medical doctor, not a barber surgeon. It is also possible that Rüss enjoyed imperial support, since the stylized portrait in the border at lower left certainly looks like Holy Roman Emperor Maximilian I (1459–1519). Augmenting this imagery, the page’s textual information further portrays a medical practice defined by astronomical, religious, and calendrical timing. In the registers below Cosmas and Damian, we find information about the new, full, and quarter moons; the hours of the day; saints days and Easter; good and average times for bloodletting and medicinal bathing; when to wean babies, take medical treatment, or plant—which, in this instance, likely refers to pharmacological plants and herbs, as opposed to agriculture more generally.    

In addition to the vertical stacks of days and months dictating the overall layout, there are a few key computational elements to note at the top of the page. Several of these stand out to modern eyes as illegibly foreign. Note, for example, references to figures like the “Golden Number” [güldin zal], the “Dominical” or “Sunday Letter" [der Sontagbüchstab], and the “Sun Cycle” [der Sonnen circel], to name three. The Golden Number, in chronology, is a lunar calculation; it was used to specify the dates of all the new moons in a solar calendar year. Indicated by a number between 1 and 19, it marked a particular year of the Moon’s progression within the 19-year Metonic cycle.* According to the calendar above, the Golden Number for the year 1519 was “XIX.” The Dominical or Sunday Letter is again tied to chronology. It refers to one of seven letters—i.e., A, B, C, D, E, F, or G—used in almanacs, ephemerides, and calendars to denote the Sundays throughout the year. The letter “A” was linked to January 1, “B” to January 2, and so on up to letter “G.” If January 1 happened to be a Monday, then the year would be designated a “G” Dominical-letter year and all of the Sundays would be marked with the letter “G.” The calendar above, however, shows that 1519 was instead a “B” Dominical-letter year, meaning January 1 was a Saturday. Finally, the Sun Cycle is a 28-year cycle of the Julian calendar that accounts for leap years; it expresses a relationship between the days of the week and the dates of the year by using a number between 1 and 28. As we see above, the Sun Cycle for the year 1519 was “XVI.” The inclusion and presentation of these variables is ultimately consistent with the type of wall calendars that were produced by university scholars. Here, then, we might speculate—in line with Darin Hayton’s work on this topic—that this particular document was perhaps created to bolster Johannes Rüss’s claim to expert knowledge of both medical and astrological timing.

The gallery below pictures a range of calculators—dating from 1474 to 1540—that were designed to reckon the various timing values listed above. Click on any of the images below for more information.

* The term “Metonic cycle” refers to a relationship between the cycles of the Moon and the cycles of the Sun. Named for the 5th century (BCE) Greek astronomer Meton of Athens, it describes a period of 19 years—or 235 lunar months—after which the new moon again occurs on the same day of the year.

Popular Prognostication: A Farmers Almanac

The two-page calendar, at right, paints a slightly different picture of the wall calendar and its medical-astrological applications. Gone are the complex calculations, physician saints, and text-based layout seen above. Instead we find images—lots of them—as well as the name of a printer, as opposed to a physician. The large, red letters at the bottom of the second page read: “Printed in Zürich by Christoffel Froschouer.” Christoffel Froschauer (ca.1490–1564) is best known as the printer of the so-called “Zürich” or “Froschauer Bible,” the highly illustrated German-language Bible translated by Huldrych Zwingli (1484–1531). This calendar by Froschauer exemplifies a particular genre of wall calendar from the sixteenth century known as the Bauernkalender or “farmers almanac.” This type of calendar featured little or no text; it instead communicated a wealth of astrological information through conventional symbols, whose meanings were rooted in oral traditions shared by the literate and illiterate alike. Their visual emphasis, low cost, and high print runs also meant that calendars of this kind were accessible to a very broad audience. Printers, like Froschauer, took advantage of this large demand. As the Protestant reformer and famed defender of astrology Philip Melanchthon (1497–1560) put it: “…anyone can have the letters of the Calendar on his wall!”

Click the images above for more information.

Anyone may have been able to own such a calendar, but how did they read it? Starting at the top of the first page, the black-and-red title reads: “Calendar for the Year 1541." Below this, two images provide further context. At left, we see a Zodiac Man at the center of a celestial wheel, with threads tethering his various parts to their respective sign rulers. At right, the Zodiac Man’s pictorial pendant is a scene of surgical practice. It shows a woman seated in a large, stable chair with a pan between her knees, attended by a physician, who phlebotomizes her left arm. The text between these two images is the legend or key; it clarifies the symbols used in the registers below. The first column covers the following topics: good and average days for bloodletting; cupping [schräpffen] and bathing; medical potions and digestives [püllulen]; electuary [latwaeryen] remedies; weaning children [Kind entwennen]; planting and sowing; plowing/fertilizing; waning [Uffgang] and waxing [Abgang] Moon phases; as well as the days the Sun enters a new Zodiac sign. The topics in the second column include the New Moon, First Quarter Moon, Full Moon, and Last Quarter Moon phases; cold days; snow days; damp days [fücht]; rain days; windy days; warm days; and special days. Below this list, the layout of the lower registers yields a few further topics to note. First, the months and their associated labors comprise the left vertical axis. Second, the lines extending horizontally across the page mark the days of the month with triangles and, below this, the position of the Moon by Zodiac sign. Third, the red triangles are Sundays and the non-repeating characters above are Saint’s days. Fourth, two supplementary—and notably accurate—eclipse prognostications are provided: a large black circle marks the total lunar eclipse that occurred on 12 March 1541, while a black-and-white, wavy-rayed sun predicts the partial solar eclipse that indeed occurred on 21 August 1541.  

Putting all of this information together, we can see that February [Hornung] of 1541 would be the time to kick off shoes and immodestly warm oneself by a blazing fire; or, in case of toothache, Saint Apollonia’s Day—the patron saint of dentistry—would perhaps be the time to schedule an extraction, since the strong winds predicted for the following day might keep one homebound anyway. On the calendar, this would be February 9, which falls between the Sun’s ingress into Pisces on February 8 and the Full Moon in Leo on February 10. Though, if toothache were not one’s only ailment, the few days prior would perhaps be a good time for cupping and medicinal bathing, or perhaps even a bit of bloodletting treatment. With the Moon in Cancer on these days, the physician would be expected to avoid the body’s Cancer-ruled parts, which —as the Zodiac Man reveals—include the breast and stomach.     

A calendar for medical astrology first and foremost, this document’s predictions were understood to apply to a range of other topics, like farming or travel as well. Offering all-purpose prognostication for many, this calendar speaks to a general healing practice oriented around astronomical, religious, and calendrical timing—in other words, not individual considerations.

Diagnostic Diagrams: Assessing Seasonal Influence

Click on the image for more information.

Implicit in the wall calendar’s medical and meteorological prognostications was the issue of seasonal timing. Owing to the movements of the celestial spheres, seasonal change was widely regarded as a primary sublunary factor in human health. In his work on ancient medical ethics, Paul J. Carrick helpfully describes this phenomenon as the principle of seasonal influence. The calendrical diagram at left helps explain this idea. Notice first that the center of the wheel is divided into four parts, and that these quadrants feature the following labels: Phlegmatic [Flegma.]; Melancholic [Melanc.]; Choleric [Coleri.]; and Sanguine [Sangui.]. These terms are tied to humoral theory. They describe physiological and psychological temperaments deriving from particular humoral balances. The basic premise of humoral medicine, at this time, was that the human body consisted of Four Humors—i.e., Blood, Yellow Bile, Black Bile, and Phlegm—which were produced by four internal organs: the Heart [Blood], the Brain [Phlegm], the Liver [Yellow Bile], and the Spleen [Black Bile]. These Four Humors, in turn, shared with The Four Times of Year—i.e., Spring, Summer, Fall, and Winter—a conceptual and structural grounding in The Four Elements—i.e., Air, Fire, Earth, and Water—and The Four Elementary Qualities—i.e., Hot, Cold, Dry, and Wet. The calendar wheel expressly knits these notions together, mapping them onto the Twelve Months, The Twelve Signs of the Zodiac, the Twelve Winds, and The Four Cardinal Directions. In the process, the calendar exemplifies this principle of seasonal influence and timing. By linking The Four Times of Year to The Four Humors, it causally connects seasonal change to the onset of certain diseases. It shows The Four Times of Year that each person—depending on their humoral constitution—might be vulnerable to catching a particular disease

“The Four Times of Year, the Nature and Qualities of Each, Plus the Months, Signs, and the Winds” (1528). Click on the image for more information.

The diagram at right further details these temporal and physiological synchronizations. Dating from 1528, this instructive image represents “The Four Times of Year, the Nature and Qualities of Each, Plus the Months, Signs, and the Winds.” The paragraphs below provide translations of the diagram's text. These translations proceed from center to periphery and follow a conventional sequence that begins with Spring and ends with Winter. Each circle then repeats this same progression.
First [Innermost] Circle: The center of the diagram identifies The Four Times of Year—Spring [Blentz]; Summer [Sumer]; Fall [Herbst]; and Winter [Wÿnter]. Appended to the seasons are images representing The Four Elements. Two anthropomorphized clouds spewing wind represent “Air” [and Spring]; stylized flames represent “Fire” [and Summer]; a town surrounded by mountains represents “Earth” [and Fall]; and fields, presumably ice-capped or with a flowing stream, represent “Water” [and Winter]. Note: these images are the same as those featured in the 1472 edition of Isidore of Seville’s De responsione mundi et de astrorum ordinatione.
Second Circle: The second concentric circle lists The Four Elementary Qualities and the particular combinations associated with The Four Times of Year and The Four Humors. The qualities for Spring are “hot and wet” [warm unnd fücht]; for Summer, “hot and dry” [warm unnd trucken]; for Fall, “cold and dry” [kalt unnd trucken]; and for Winter, “cold and wet” [kalt unnd fücht].
Third Circle: The third circle identifies three different topics. The innermost layer of text lists two: The Four Temperaments and The Four Elements. These two topics are again aligned with The Four Times of Year: Sanguine [Sanguine] and Air [Luft] with Spring; Choleric [Cholericus] and Fire [Feür] with Summer; Melancholic [Melancholicus] and Earth [Erd] with Fall; Phlegmatic [Flegmaticus] and Water [Wasser] with Winter. Above this, the outermost layer of text lists the Twelve Months. Three months are given to each of The Four Times of Year: March [Mertz], April [Apprill], May [Mey] are grouped with Spring; June [Brachmonat], July [Hewmonat], and August [Augst] with Summer; September [Herbst], October [Weinmonat], and November [Wintermonat] with Fall; and finally, December [Christmonat], January [Jenner], and February [Hornung] with Winter.  
Fourth Circle: The Fourth Circle names the Twelve Signs of the Zodiac. Aries [Wider], Taurus [Stier], and Gemini [Zwilling] are aligned with the Spring quadrant. Cancer [Krebs], Leo [Leo], and Virgo [Jungkfrow] are part of the Summer quadrant. Libra [Wag], Scorpio [Scorpio], and Sagittarius [Schutz] are aligned with the Fall quadrant. Capricorn [Steinbock], Aquarius [Wasserman], and Pisces [Fisch] are part of the Winter quadrant.
Fifth Circle: The Fifth Circle identifies the Twelve Winds, which are listed above each of the Twelve Signs. Corus sits above Aires; Aquilo above Taurus; Boreas above Gemini; Vulturnus above Cancer; the “East Wind” [Subsolanus] above Leo; Eurus above Virgo; Notus above Libra; Auster above Scorpio; Aphricus above Sagittarius; Zephyrus above Capricorn; the “West Wind” [Fauonius] above Aquarius; and Circius above Pisces.
Sixth [Outermost] Circle: The Sixth Circle lists two topics: The Four Times of Day and The Four Cardinal Directions. Aligned with the horizontal and vertical axes are The Four Times of Day: (Sun) Rise [Auffgang]; Midday [Mittag]; (Sun) Set [Niedergang]; and Midnight [Mittnacht]. Set in between these axes are The Four Cardinal Directions: East [Oriens] at upper left; South [Meridies] at upper right; West [Occidens] at lower right; and North [Septen] at lower left.

In line with The Four Elements, Temperaments, and Times of Year, medications were also associated with different combinations of The Four Elementary Qualities—Hot, Cold, Dry, Wet. This logic underlies the calendrical scheme in the image below, which comes from Ars magna lvcis et vmbrae (1646) by Athanasius Kircher (1602–1680). This image portrays both physical maladies and pharmacological remedies as part of an interconnected universe with the human body at its center. The figure’s star-obscured loins and coiled intestines make this connection somewhat explicit, as do the calendar wings on either side. Featuring the Twelve Months and Zodiac Signs, the calendar’s outer columns point to the significance of solar and lunar timing for health-related matters. The inner columns map medicinal remedies onto the body in accord with this timing and its elementary qualities. Notice, for example, the remedies listed at the intersection of July, August, Leo and “Medicamenta simplicia” [simple drugs]. Here we find Cinnamomum, a type of aromatic evergreen tree from which cinnamon is derived. Like the month of August and the sign of Leo, Cinnamomum was associated with the quality of hotness. It was said to warm and mollify the heart: an organ likewise linked to hotness through its zodiacal ruler Leo. Linking this information together, the table thus lists Cinnamomum as remedy for diseases characterized by an excess of hotness, like Cardialgia or heart burn. 

Microcosmic Man and "Celestial Medicine." Ars magna lvcis et vmbrae (1646): Iconismus XVI, Fol. 533. Click the image for more information. 

Under the Weather

The image below makes explicit the connection between general medical astrology and meteorology. This image comes from Robert Fludd’s Philosophia sacra et vere Christiana seu meteorologia cosmica (1626) and is entitled “meteorological precious stone.” It illustrates the influence of the Moon, Sun, and planetary bodies on the terrestrial sphere by means of weather phenomena. Historian S. K. Heninger, Jr. explains that, following Aristotle, Renaissance writers used the word “meteors” to describe the continual succession of weather phenomena in the sublunary sphere. In the image, this succession of weather is shown as an impressive assortment of clouds, vapors, rainbows, and meteors, among other objects. These objects, however, also have another meaning: they present the passions and diseases as the meteors of Man’s body.

"Catoptrum Meteorographicum," Philosophia sacra et vere Christiana seu meteorologia cosmica (1626). Click the image for more information.

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