Agora: Red Deer Polytechnic Undergraduate Journal
Volume 15:2 (2024) Student Writer Awards

How Astrology Survived the Rise of Christianity: A Brief
Literature Review
Danica Madsen
The practice of astrology is something that has been highly contentious over time. Its utility
and validity have been both defended and denounced by many, and yet it still exists (although to
varying definitions and degrees) in modern times. It is my opinion that the scientific properties of
astrology are what allowed astrology to stand the test of time. The following discussion will
examine the Early to Late Middle Ages when within the practice of the Christian religion, it was
seen as heretical to practice astrology. I hope to exemplify both the arguments against astrology
put forth by Christian scholars, and to show examples of how astrology managed to stay relevant
despite this denouncement.
As defined by Loar (2018), Astrology is a “fundamental search for meaning by observing
cycles and interpreting correspondences between celestial occurrences, planetary positions, human
affairs, and terrestrial events.”(131). This definition encompasses both calculation and meaning.
This principal understanding is necessary to properly appreciate the aims of astrology as either a
Religious System, a Philosophy, a Science, or a combination of all three. Upon its transmission
from pre-Babylonian Sumerian cultures to that of the Romans and Greeks, astrology’s use was
predictive and informative in nature and was used in terms of omens and the determination of large
scale agricultural and social events (Beck, 2006). At this time astrology was both scientific, using
observation and calculation with respect to the fixed stars, planetary movements, and their
respective positions in the zodiac, and philosophical in terms of bringing meaning to these
phenomena as they related to mundane earthly events.
There were several different types of astrology being regularly practiced in the centuries
following the turn of the millennium. Hegedus (2007) notes several prominent astrologers
including, Manilus, Ptolemy, Vettius Valens and Firmicus Maternus (1), and from these authors we
see various kinds of practical astrology emerging. Examples of these include Melothesia or
Medical Astrology, in which the cosmos were said to influence specific parts of the human body
and had assignments to their respective body parts in terms of illness diagnosis and notable times
in which the application of medicine would be most beneficial (Hegedus 2007, 2). The most
obvious example of this is that of the Zodiac Man (see appendix). Further examples include
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Catholic Astrology which was said to govern individual zones of the earth (Hegedus 2007, 6), and
Genethlialogy Astrology which is commonly known as individual birth charts i.e. mapping the
position of the stars and planets and determining their placements in the zodiac at the moment of
an individual’s birth (Hegedus 2007, 6). Pingree (2001) elaborates on this list beginning with the
addition of Catarchic Astrology (the most favorable time for commencing any activity,) which was
further divided into several subtypes including Medical Astrology, Marriage Astrology, and
Military Astrology (18). Pingree (2001) notes that Catarchic Astrology eventually gave birth to a
new science referred to as Interrogational Astrology, and this broadened the definition further to
allow for event prediction for any given phenomenon brought forth by the querent (19). These
examples illustrate that the science of astrology was a growing practice and quite common place.
The philosophical portion of Astrology could be viewed as religion respectively as it
integrated the animism of gods in terms of their archetypal planetary meanings, and these meanings
subsequently guiding the interpretations of the mathematical calculations. The cultural/astrological
belief at the time was that all things have a spirit (specifically celestial objects in this instance,)
and that explicit daily rituals and practices would in turn placate these gods or spirits. The
observance of these rituals would determine terrestrial reality in either a positive or a negative way.
The polytheistic views of the Greeks and Romans at the time of transmission supported the
integration of these astrological principles into their pagan belief system. In his book Early
Christianity and Ancient Astrology, Hegedus (2007) asserts that these religious connotations
imbedded in astrological doctrine are a main source of tension in terms of the Christian rivalry
with astrology that would ensue (10).
Kern-Ulmer (1996) further notes that within ancient Greek literature, astrological
principles/magic were employed using the technique of sympathies. The energy of the cosmos
could be interjected upon in either a sympathetic (additive) or antipathetic (subtractive) nature to
bring about a desired outcome in the realms previously mentioned. Because it was the cosmos that
determined all natural phenomena based on celestial movements, and the deities that were being
ritualized and obeyed were archetypically representative of the planets, the implication of
performing astrological magic/ritual was then to placate the cosmic realms (Gods) to bring about
beneficial outcomes for the earth, its objects, and its inhabitants through this idea of sympathies.
Hegedus (2007) asserts that, “The doctrine of cosmic sympathy was based not only on observation
of “…natural phenomena but also, in religious contexts, on divine revelation.” (2) The author
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stresses that this left little room for the biblical view of the “divine creator who was external to the
universe,” and “undermines Christian views of divine providence and free will.” (Hegedus 2007,
12).
Beginning in the fourth century as Christian doctrine became more mainstream there is an
emergence of literature that mirrors the sentiments above that was designed to denounce astrology
as paganistic and heretical. Astrology and its association with fatalism and magic came to be seen
as an implausible system and was denounced for its contrariness to that of free will and divine
creation (Hegedus 2007). According to many Christian scholars of the time, astrology was not to
be ascribed to along side the acknowledgement of the Christian faith. Numerous influential figures
such as Basil of Caesarea, St. Ambrose, St. Augustine, and Origen presented multiple texts arguing
against astrology and its validity on these grounds (Hegedus 2007).
Hegedus (2007) consolidates five common arguments against astrology by these authors
in his text as follows: 1) The argument of practical impossibility; 2) The argument of different
destinies; 3) The argument of common destinies; 4) The arguments from animals; 5) The moral
argument (25). Regarding each of these arguments, the author spends a great deal of time citing
clear examples from original text, indicating their intended rational (Hegedus, 2007). While the
total extrapolation of each argument and the concurrent view by each author is beyond the current
scope, there appeared a common goal amongst the early Christian scholars to denounce predictive
astrology within the emerging Christian framework of the time.
Despite these arguments, astrology did survive throughout the early Middle Ages. In the
text, Hexemeron of Saint Basil the Great and cosmological views of his time, Danezis,
Theodossiou, and Dimitrijevic (2005) address the Hexemeron of Saint Basil the Great as an early
account of astrological principles being amalgamated into the science of astronomy. Although
Saint Basil is noted as an early advocate of Christianity, he was also a “deep connoisseur of
astronomy and the physical sciences,” (Danezis, Theodossiou, and Dimitrijevic 2005, 105). Saint
Basils’ adoption of cosmological ideas is described as very “harmonious” to those of the ancient
Greeks, Babylonians, and Egyptians in terms of star cycles, the existence of the zodiac and
declinations of planets. The assertion here is that this similarity is likely a result of Saint Basil
having spent time in regions of Mesopotamia in his youth where these cosmological ideas are seen
to have originated (Danezis, Theodossiou, and Dimitrijevic 2005, 104). In his discourse however,
Saint Basil does not mention the astrological doctrine that would have informed his astronomical
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observances, but rather has a discussion regarding the origin and existence of time as it relates to
the creation story of Genesis (Danezis, Theodossiou, and Dimitrijevic 2005, 103).
Arguments such as this begin the apparent dissection of Astronomy as a science versus the
heretical doctrine of predictive Astrology. This dissection is of importance as it allows the
utilization of very real and necessary scientific principles regarding the cosmos and their relation
to natural earthly phenomena, whilst leaving behind the morally inadequate ideas such as casting
birth charts, ritualizing planets as Gods and believing that planets had more control over people
and terrestrial events than “God” the Christian creator. Hegedus (2007) argues that discourse in
the Almagest by Ptolemy also inadvertently helps to legitimize this dissection. The scientific and
mathematical nature of the Almagest allows for “Astronomy” to become legitimized due to its
practical and testable nature, while assigning the Tetrabiblous to the philosophical and interpretive
realm of “Astrology.”. It is of convenience regarding their goals to denounce astrology as a
religious/philosophical tradition that many scholarly arguments leave behind the Tetrabiblous
whilst ascribing to the mathematical principles in the Almagest. Hegedus (2007) suggests that the
language and conceptualization used by Ptolemy in his own text in effect creates a basis for a
distinction between philosophical forms of “Astrology” and the scientific practice of “Astronomy.”
(5).
With respect to the critical adoption of astronomical sciences within the Christian societal
framework, Laistner (1941) explains that during the Carolingian Age (approx. 800 – 887 C.E.) an
anonymous letter is found that stresses the omission of Astrology and Medicine within the subjects
of the quadrivium as problematic and dates this omission back to the time of Isidore. The
quadrivium was a section of the seven liberal arts (geometry, astronomy, music, and mathematics)
that structured early monastic curricular study (Backman, 2022), and at its earliest outset was said
to “introduce skills needed for the liberal, symbolic and allegorical interpretations of the Holy
Writ,” (Backman 2022, 107).
In The Etymologies, the Latin Bishop Isidore of Seville does clearly ascribe to astronomy
(part of the quadrivium) as an area of study and notes it as the detailed reading of the stars and the
courses of their constellations as relative to earth (Barney et al. 2015, 99). What is important with
respect to the sentiments by our anonymous author is that Isidore openly separates the science of
astronomy as “…the turning of the heavens, the rising, setting, and motion of the stars, and where
the constellations get their names.,” and astrology as “…partly natural and partly superstitious.”
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(Barney et al. 2015, 99). Isidore displays clear astrological knowledge and asserts the necessity of
such knowledge for navigation by sea and prediction in terms of seasonal qualities, but for this he
references only the fixed stars. When making mention of the planets and zodiacal signs Isidore,
clearly states that the worship or adherence to belief in these (planets and signs) is a belief
strengthened by the devil and is paganistic (Barney et al., 2015).
Although Isidore displays knowledge of the traditional/ancient meanings given to the
planets and the zodiacal signs, he is very clear in that he believes these ideas to be anti-Christian,
“Therefore, observations of the stars, or horoscopes, or other superstitions that attach themselves
to the study of the stars, that is for the sake of knowing fates – these are undoubtedly contrary to
our faith, and ought to be so completely ignored by Christians that it seems they have not been
written about.” (Barney et al. 2015, 106); but belief in the fixed stars (i.e. astronomy) was noted
to be in alignment with Christianity, “But whatever the type of superstition with which they have
been named by many men, the stars are nevertheless things that God created at the beginning of
the world, and he set them in order that he might define the seasons by their particular motions.”
(Barney et al. 2015, 106).
Regarding medical doctrine there is also an astrological omission in his text. Isidore
describes his understanding of medicine and outlines three distinct schools therein; one of which
is rational and attributed to Hippocrates. Isidore ascribes to the Hippocratic doctrine of the four
humors as the four elements of the body that are the cause and cure for illness (Barney et al. 2015,
109). Although Isidore describes in detail his understanding of the Humors, how they are seen to
cause disease, and that sympathetic remedies are incurred to help with these ailments, he makes
no mention of the astrological doctrine aside from his brief discussion of critical days (as seen
earlier the idea of critical days is derived from catarchic astrological doctrine) (Barney et al., 2015).
In Passions and Tempers: A History of the Humors., by Noga Arikha (2007) it is further noted that
“To each humoral category would eventually correspond also to a time of day, a color, a taste, a
type of fever, a main organ, governing musical modes, a tutelary planet and a set of astrological
signs.” (11). Again, within the medical discourse of Isidore’s Etymologies we see the divergence
of astrological science and philosophy with the dissection of astronomy from its original
astrological forms.
In the “foundations of medicine” section Isidore does mention the necessity of geometry
as a system of knowledge in that it allows the physician to be aware of the “qualities of the regions
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and location of places, may he teach what the person should attend to there.” (Barney et al. 2015,
115) and a mention of astronomy in so far as “…he may observe the logic of the stars and the
change of seasons. For, as a certain physician says, according to their mutations our bodies are also
changed.” (Barney et al. 2015, 115); but again, makes no association between these principles and
those of their astrological roots i.e. melothesic and catholic astrology.
As we move into the later Middle Ages, we see a huge transmission and revival of ancient
texts that make their way from Africa into the European region (Clark 1995). Within these texts
are large amounts of information regarding ancient astrological doctrine and a revival can be seen
as Raymond of Marseilles begins to spread the new science of these texts throughout Europe (Clark
1995). There is evidence that Raymond was cognizant of the Christian church when revitalizing
and disseminating these documents, and he is careful to align himself and his mission alongside
that of the Christian Church (Clark 1995). Raymond asserts that “God himself wishes us to study
the stars…: (Clark 1995, 95) and that “The planets indicate nothing unless God predestines them
to.” (Clark 1995, 95). Raymond goes on to cite works by Arabic scholars such as Abu Ma’shar as
he praises the use of astrology in medicine, describing the validity of physicians learning the
courses of the planets to provide accurate medical care (Clark 1995). Raymond did not go without
his adversaries, but Clark (1995) notes that there was in fact an “uncomfortable marriage of
Christianity and astrology.” (99) emerging at this time.
Lastly, I would like to turn to the afore mentioned Zodiac Man. The Zodiac Man is the
illustration of a male figure, standing with his legs and arms slightly spread, depicting the twelve
images of the Zodiac superimposed on his body from Aries (the head) to Pisces (the feet) (Clark
1982, 1). Clark (1982) describes the zodiac man as a quick reference guide for physicians,
surgeons, and laymen to determine which part of the body was ruled by which astrological sign.
The information provided by the Zodiac man was used to guide treatment (alongside the placement
of the moon) and was a practice which began with Ptolemy in the first century and was carried on
throughout the Middle Ages (Clark, 1982). The ancient conception of the Zodiac Man was drawn
upon via the concept of as above so below, the microcosm within the macrocosm, which forms the
basis for astrological doctrine itself (Clark, 1982). Clark (1982) notes that the foundation of the
Hippocratic model is also derived from these principles and created the groundwork for his
humoral theory. Clark (1982) cites use of the Zodiac man throughout the Middle Ages with
examples such as Manilus’ list of correspondences that appear in his writing between 704-709
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(Clark 1995). Again, we see a clear indication that in terms of science, i.e. medicine, there were
astrological principles that were adopted despite the Christian arguments regarding astrology as
heretical and of no use.
Although this review is clearly not inclusive of all possible texts and instances referring to
the Christian treatment of astrology and the reasons for which astrology remained valid throughout
the Middle Ages, I do hope to have highlighted that the scientific use of astrology was instrumental
in its survival throughout this time. Despite the denouncement of many different influential
Christian Scholars, there seemed no way to “get around” the guidance of the cosmos when it came
to certain aspects of daily life i.e. navigation, seasonal changes, and of course in medicine. The
utility of astrology in these realms led the critics of the time to adopt a dissective model that
allowed for the separation of certain tenets within traditional astrological doctrine from that of
scientific astronomy, a phenomenon we still see today. It is this dissection that allowed certain
forms of astrology to remain quietly active throughout the Middle Ages until the transmission of
ancient texts flowed back into the region, further revitalizing the practice. It is my hope that in the
future, as astrology continues to become more “mainstream” and accepted, we can again see the
convergence of science and philosophy and this ancient system can be utilized to its full extent
moving forward.

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Appendix

“Red/Black Zodiac Man in Wheel”
https://onlineexhibits.library.yale.edu/s/medicalastrology/media/15529

Bibliography
Arikha, Noga. 2007. Passion and Tempers: A History of the Humors. HarperCollins.
Barney, Stephan A., W J. Lewis, J A. Beach, and Oliver Berghof. 2015. The Etymologies
of Isidore of Seville. Cambridge University Press.
Backman, Clifford R. 2022. The Worlds of Medieval Europe. 4th ed. New York: Oxford
University Press
Barton, T. Ancient astrology. (1994). ProQuest Ebook Central https://ebookcentral.proquest.com
Beck, R. A brief history of ancient astrology. (2006). ProQuest Ebook Central
https://ebookcentral.proquest.com
Clark, Charles. "The Zodiac Man in Medieval Medical Astrology." (1982). Accessed April
6,2024.
https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=1691&context=rmmra.
Clark, Charles W. "A Christian Defense of Astrology in the Twelfth Century: The Liber Cursum
Planetarum of Raymond of Marseilles." International Social Science Review 70, no. 3 &
4 (1995): 93-102.
Danezis, Emmanuel, Efstratios Theodossiou, and Milan S. Dimitrijevic. "Hexameron of Saint
Basil the Great and Cosmological Views of His Time." Science and Orthodoxy: A
Necessary Dialouge, no. October (2005): 103-109.
Hegedus, Tim. 2007. Early Christianity and Ancient Astrology. Peter Lang.
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Kalender vff das M.D.XXXX1. Jar. (Zurich:Getruct by Christoffel Froschouer, 1541.
https://onlineexhibits.library.yale.edu/s/medicalastrology/media/15529
Kern-Ulmer, B. “The Depiction of Magic in Rabbinic Texts: The Rabbinic and the Greek
Concept of Magic.” Journal for the Study of Judaism in the Persian, Hellenistic and
Roma Period 27, no. 3, (1996): 289-303
Laistner, M L. "The Western Church and Astrology During the Early Middle Ages." The
Harvard Theological Review 34, no. 4(Oct) (1941): 251-275.
Loar, J. 2018. "Ancient Star Maps." Atlantis Rising Magazine.
Pingree, David. "From Alexandria to Baghdad to Byzantium. The Transmission of Astrology."
International Journal of the Classical Tradition 8, no. 1 (2001): 3-37.

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