Searching for Astrologers in Early Medieval England (Part 1: Continental Connections)

(+ Old English worksheets)

Is it possible to find traces of a horoscopic astrological practice in England between the eighth and eleventh centuries? Delving into the recollections of Aldhelm and Bede, the laws of Cnut, the homilies of Ælfric and other sources, this summer we’re on the hunt for astrologers in the period prior to astrology’s commonly cited twelfth-century revival in the Latin-speaking West.

In July, we jump from England to the Continent, querying the role of naked-eye observation, mathematical calculations, and horoscopic traces.

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I’m convinced that the ghosts of historical heavyweights like Charles Homer Haskins and M.L.W. Laistner will visit me in my sleep after I publish this. Much like the nocturnal visitors that showed Ebenezer Scrooge the error of his ways, my somnial spirits will likely urge me to reconsider the trajectory of my research.

“Don’t you know that ‘scientific astrology’ all but disappeared in the Latin-speaking West after Rome’s fall?” Laistner might ask. His thesis is well-known to anyone who has engaged with Valerie Flint’s scholarship in the 1990s. Her study, The Rise of Magic, is essential reading for anyone curious about the recovery of astrology, magic, and divination in the Early Middle Ages.¹

Flint’s contention that more may have been happening in the realm of “scientific astrology” than Laistner originally concluded has and continues to inspire my research, particularly as her work did not fully address the more technical side of astrology, including horoscopic astrology.

In this article, we’re going to unpack a few traditional views of astrology in the Early Medieval period and ask whether we can find any traces of astrologers or even an astrological practice in surviving manuscripts.

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“Popular” vs. “Scientific” Astrology: A problematic dichotomy?

Categories can be helpful—they can assign, organize, and clarify. However, categories are equally problematic for sometimes establishing artificial, anachronistic, and exclusionary boundaries that can become problematically entrenched in scholarship. In my small corner of the Middle Ages, the narrow fields of prognostics and astrology have their own issues around framing, conceptualization, and labelling that, I’d argue, aren’t discussed enough. For one, the term “prognostics” has long been applied to an expansive collection of loosely predictive texts—texts that have often been selected, collected, and studied alongside other (sometimes vaguely) future-oriented texts.

Longtime readers will already be familiar with many of these prognostics; for newcomers, these texts can vary from schedules for optimal bloodletting days according to the lunar cycle, to days prescribed as “evil” according to the solar calendar, to agricultural predictions for the year ahead based on the day of the week that January 1 falls, and several other unique and technically “predictive” texts. The problem: taken together, these texts employ multiple temporal schemes for making judgements about the future, deploy varied “textual” devices for arriving at those judgements, and are situated in specific places in the original manuscripts in which they appear. In a way, it’s like comparing apples and oranges, or lumping ingredients together in a pantry challenge.

The tendency to categorize the abovementioned texts as “prognostics” can be as problematic as labelling one thing “popular” and another “scientific.” These two terms have been used to define and implicitly “tier” astrological knowledge and, even when qualified as not intentionally pejorative, these labels can make subtle statements about the copyists, users, and transmission of different types of “astrology.”

Reaching for a cursory definition of the term “popular,” we can see its positive connotations, like prestige or admiration by a large group or fan base. But another, more complex definition might apply to our discussion, namely, as the Cambridge Dictionary online, for example, indicates, “popular” can also “[involve] ordinary people rather than experts or very educated people.” This definition makes some exclusionary presumptions when applied to the type of astrology potentially practiced in early medieval monastic circles. (I emphasize potentially owing to the absence of any documented evidence around the use of prognostics.) Considering these tools as “popular astrology” or evidence of “popular superstition” may overlook the fact that, to a large extent, these prognostics depended on an educated, monastic milieu. Literacy, Latin fluency, calendrical construction, and basic arithmetic were all necessary components in interpreting prognostics. While beliefs around auspicious activities to be undertaken according to certain lunar phases could have been practiced among the populace, the preservation and transmission of the textual tradition required some modicum of learning.

To varying degrees, scholarship has been testing what constitutes “popular” and what constitutes “scientific.” Over the past thirty years, research into computus manuscripts, monastic learning, and pastoral culture have debated the extent to which prognostics represent vestiges of folkloric superstition, essential compromises between lay and ecclesiastical culture, and components of a learned monastic milieu.² In a way, addressing the question of “popular” versus “scientific” astrology requires us to shift our gaze, considering what prognostics do and do not attest to.

Prognostics found in manuscripts ranging from computus anthologies to private prayerbooks to medical compendia suggest that a certain degree of education was required for written transmission, thereby precluding them from entirely occupying the realm of “popular” astrology per se, even if their content occasionally overlaps with divinatory traditions “documented” in “popular” society through sermons, homilies and penitentials. (And we should always regard those sources with a much-warranted dose of caution!) What prognostics do not attest to is a sustained horoscopic astrological tradition, even if we occasionally see the term “horoscope” applied to them.

One other important point is that these “popular” astrological forms—from lunaria to the Spheres of Life and Death—survived well beyond the recovery of horoscopic astrology in the High Middle Ages. Lunaria saw increasing complexity added to their construction through the addition of various zodiacal and astrological features, while the Spheres of Life and Death remained of interest in medical circles. The revival of horoscopic astrology did not displace these tools in the Renaissance and even Early Modern period and many of these tools continued to appear in “scientific” contexts, including in the notebooks of medical practitioners.

Next month, I’ll revisit the implications of this term when used for activities taking place outside the cloister. Homilists and lawmakers may have identified and even derided local practices, but is the term “popular” helpful in characterizing and understanding those practices? For now, however, let’s remain within the monastery walls.

Where are the “scientific astrology” manuals?

A particularly sticky point in the search for astrologers in Early Medieval England is the question of texts. As Laistner maintained, it wasn’t until much later that Julius Firmicus Maternus’ astrological handbook, Mathesis, reappeared on the scene. In this case what might someone, keen on prediction through the stars, have at their disposal?

We have no surviving booklists for English libraries prior to the twelfth century. This makes the identification of cosmological and astrological texts—if there were any of the latter—particularly difficult to assess. Blame it on the Vikings, the monks themselves, or the Normans (tongue in cheek, of course!), but all these and other factors not only shaped English book production, but also acquisition from the ninth to the eleventh centuries. Only a fraction of the books once held in monastic armaria are thought to remain, though we can be sure that dynamic centres like Winchester, Canterbury, and York all likely possessed comparatively larger collections.³

In the absence of booklists, we can assemble a patchwork of information. We know that Bede had an enviable library at Wearmouth-Jarrow, while we can glimpse possible holdings at York through Alcuin’s poems. We might speculate that the “greatest hits” of the age were well-worn and often consulted—the grammar of Priscian, the encyclopedic and etymological detours of Isidore of Seville, or the thinking of St. Augustine—and scholars generally agree that staples of a monastic library may have included copies of Boethius’s De Consolatione Philosophiae (On the Consolation of Philosophy), Isidore’s De Natura Rerum (On the Nature of Things), and in later centuries, Bede’s works on natural philosophy and time reckoning.

The evidence is thinner when attempting to assess access to astrological material as Greek astrological and astronomical works remained largely inaccessible in this period. While we know that as early as the ninth century, manuscript evidence attests to the progressive collection of treatises on mathematics, astronomy, and calendar computation, it isn’t until the closing decades of the tenth century that more technical tomes, such as those on the astrolabe, appeared on the scene. When Firmicus Maternus’ astrological handbook, Mathesis, reemerged, we know that it was sought after from figures like the future Pope Sylvester II, but we have much less evidence to support the idea that centres from Fleury to Fulda understood and had at their disposal the mathematical and astronomical apparatuses available to construct a horoscope. (But, I’m still looking!)

How to cast a horoscope…

To construct a “horoscope” one needs to know the point of the ecliptic rising on the eastern horizon at a specific time and place—this is the all-important horoskopos, or “hour-marker” from the Greek. When one constructs a “horoscope,” they are technically erecting a “diagram” or “figure” based on the “hour-marker.” This figure typically includes the seven classical planets and divides the figure according to twelve segments known as terrestrial “houses,” although the term “horoscope” is often used to refer to the figure as a whole.

In modern astrological lingo, when you’re asked, “What’s your sign?”, you’re being asked for your Sun sign—popularized in the late nineteenth and early twentieth century by astrologers like Alan Leo, who sought to make astrology more accessible to the masses. However, whether from medieval calendars or from the pages of Cosmo, we know that everyone born in a particular month will share the same Sun sign. In Hellenistic and Medieval astrology recovered from Arabic sources, however, it’s the sign of the zodiac rising on the eastern horizon and the exact degree of the ecliptic that gives the horoscope its individual specificity. Even if Ælfric didn’t know how to cast a horoscope, he certainly knew that the twelve signs of the zodiac took about two hours to rise and set, as he noted in De Temporibus Anni.

This is a particularly crucial point in horoscopic construction. As one sign culminates, another reaches the nadir below the earth. From this motion, the cardines as Firmicus Maternus called them—axes or points that modern astrologers often term the “angles of the chart”—could be inferred and carefully reckoned so that, “the entire substance of Fate” could be described “in well-founded statements.”⁴ Therefore, even as the sign rising on the eastern horizon change less frequently—approximately every two hours depending on various factors—the exact degree of the ecliptic changes roughly every four minutes, making it, and not one’s Sun sign, the most personalized point of a natal chart.

The other component necessary for constructing horoscopes involves calculating longitudinal planetary positions relative to local time and space. To pronounce that one has malefic Saturn in one’s eighth house at twenty-eight degrees Taurus is not a random conclusion, but one drawn from mathematical and astronomical foundations. This is one reason why Isidore found mathematici (“astrologers”) to be so dangerous: in the reckoning of a horoscope, they undertook “harmful computations.” From Augustine to Isidore and loads of patristic authors in between, astrology in its more “natural” form used for seasonal, meteorological, agricultural, and navigational purposes was perfectly acceptable, divining one’s future was not.

For the practice of horoscopic astrology, tables of planetary positions are needed to understand planetary locations relative to local time and space. Contemporary astrologers have software that enables a chart to be instantly cast for any date past, present, or future, however, before the twelfth century, this would have been an infinitely harder task. Although computus texts contained information on the luminaries and a corrupt and incomplete set of tables for the positions of the luminaries was included in a text attributed to Ptolemy, precise horoscopic calculations would have been impossible based on computus material alone.

Yet, we know that in the seventh and eighth centuries, Aldhelm and Bede may have been conversant with elements of theoretical astrology. In Aldhelm’s letter to Bishop Leuthere of the West Saxons, he mentioned learning both astronomy and astrology under Theodore of Tarsus at the School at Canterbury, while Bede famously pronounced that astrology remains “alien” to Christian faith in De Temporibus Ratione. Both these references raise questions around just how much these heavyweights knew; after all, anti-astrological polemicists from Christianity’s early days had more than enough information about horoscopic delineation to get a tonsured dilettante interested in how one might arrive at these judgements.

Carolingian Connections

We might have more success probing the trajectory of horoscopy on the continent. In a ninth-century Carolingian manuscript sumptuously illustrated to depict the constellations through the lore of the Roman astronomer Aratus of Soli, we find a diagram that visualizes not only the signs of the zodiac on the outer ring, but also the positions of the seven classical planets inside a series of concentric circles. Various notations point to information that would have been considered “textbook” in this period, including the length each planet takes to complete a single jaunt through the zodiac. Traditionally, scholarship has viewed this image as representing thoroughly astronomical phenomena, such as the relationship between apogee and perigee—the furthest and closest points of a planet in relation to Earth.

Phaenomena / Aratus, Leiden MS Voss. Q 79, f. 93v, Leiden University Libraries, Public Domain. http://hdl.handle.net/1887.1/item:4152891

Much academic ink has been spilled on this image. The esteemed scholar on Carolingian astronomy, Bruce Eastwood, studied this image in the 1980s, the historian of ancient mathematics David Pingree and the brothers Richard and Marco Mostert furthered our knowledge of its possible dating. Christopher de Hamel included it in his Meetings with Remarkable Manuscripts, and, most recently, Anne Lawrence-Mathers questioned whether it might contain “horoscopic” elements.⁵

This last contention is the most interesting to me, particularly because there can be a tendency in some scholarly circles—and this is certainly not what Lawrence-Mathers was guilty of—to see astrology where we may only, in fact, see astronomy. Planets identified in their zodiacal signs do not astrology make, while, one could argue, schematics of planetary positions relative to a geocentric position may be murkier. If a monk in Aachen went outside and noted that the sign of Libra was rising at the moment that he observed Venus in Cancer culminating, would this be horoscopic, especially since we have some version of an hour marker?

One definition of astrology suggests the correlation between celestial movements and configurations with human affairs and terrestrial events, consequentially noting the importance of correlations between the sky and earth. A natal chart may be cast with all the planets in the appropriate zodiacal signs, but, implied in the above, astrology requires a judgement to be made about those celestial positions and configurations. Thus, a natal chart may be considered celestial or astronomical on some level, but astrology involves a process. Mars in Capricorn can be an astronomical statement. At the moment that I’m typing this first draft, my astronomy app indicates that the sign of Pisces is rising and Venus is in Taurus, just beginning to creep to the south of the constellation’s most famous star cluster, the Pleiades. These are not astrological. But, telling someone that their Mars in Capricorn on the midheaven signifies power, drive, determination, and a possible future career as a lauded captain of industry smacks of the stuff that gets Neil deGrasse Tyson shouting pseudo-science.

The trouble is that it isn’t until later centuries that we get detailed astrological delineations and even evidence of predictive continuous horoscopy. A few summers ago, I read the thirteenth-century astrological autobiography of Henry Bate of Mechelen—a surviving description of an individual’s own assessment of their natal chart and predictions about what they believed might happen in future years thanks to the casting of annual charts for the moment that one’s sun returns to the exact degree and arcminute of its natal placement. I can certainly say that I have yet to come across anything comparable from two centuries earlier.

However, we should also remember that naked-eye sky observation was an essential feature of daily monastic life as I noted in an ALWOD posted during our month of Byrhtferth of Ramsey-inspired computus vocabulary. Surviving letters from Charlemagne to Alcuin and Dungal suggest a particular interest in astronomical occurrences and knowledge, the Anglo-Saxon Chronicle records striking celestial phenomena, and even the Annales regni Francorum pepper planetary observations among recorded diplomatic events.

While the Leiden diagram might have depicted the planets in the zodiac signs from a geocentric perspective, we can also recognize the challenges inherent in constructing such diagrams based on anything other than naked eye observation. Scholars such as Stephen McCluskey have noted this, indicating that continental computists likely arrived at the positions of the superior planets, Mars, Jupiter, and Saturn, this way, while David Juste has identified procedures that can identify the position of planets in the zodiac signs based on simple calculations derived from both the Septuagint and the planetary periods.⁶ Nonetheless, these and other mechanisms would likely have yielded approximate positions at best. What the Leiden image and images like it may demonstrate is that something was going on, both on the Continent and in England—something that might help us press the boundaries of this question and ask whether astronomical foundations were giving way to astrological queries.

Come back next month as we investigate if Byzantium could have been a source of astrological knowledge in Early Medieval England and what the heavy-hitters of the Benedictine Reform can tell us about magical and divinatory practices in this period.

1. M.L.W. Laistner, “The Western Church and Astrology During the Early Middle Ages,” The Harvard Theological Review, 34.4 (1941), 251-275; Valerie Flint, The Rise of Magic in Early Medieval Europe (Princeton, NJ: Princeton University Press, 1991); Flint, “The Transmission of Astrology in the Early Middle Ages,” Viator, 21 (1990), 1-27.

2. For example, although not exhaustive, these opinions may be compared and contrasted through Faith Wallis, “Medicine in Medieval Calendar Manuscripts,” in Manuscript Sources of Medieval Medicine: A Book of Essays, ed. by Margaret R. Schleissner (New York: Garland, 1994), pp. 105-143; Stephanie Hollis, “Scientific and Medical Writings,” in A Companion to Anglo-Saxon Literature, ed. by Phillip Pulsiano and Elaine Treharne (Oxford: Blackwell, 2001), pp. 188-208 (p. 192); Carine van Rhijn, “Carolingian Rural Priests as Local (Religious) Experts,” in Gott Handhaben: Religiöses Wissen im Konflikt um Mythisierung und Rationalisierung, ed. by Steffen Patzold and Florian Block (Berlin: Walter de Gruyter, 2016), pp. 131-146; Roy Liuzza, “Anglo-Saxon Prognostics In Context: A Survey And Handlist of Manuscripts,” Anglo-Saxon England 30 (2001), 181-230.

3. A few interesting studies of English book production and collecting include, Helmut Gneuss, “Anglo-Saxon Libraries from the Conversion to the Benedictine Reform,” in Books and Libraries in Early England (Aldershot: Variorum, 1996), II, pp. 643-688; Michael Lapidge, The Anglo-Saxon Library (Oxford: Oxford University Press, 2006); Elmer D. Johnson and Michael H. Harris, History of Libraries in the Western World, 3rd edn (Metuchen, NJ: Scarecrow, 1976 [1965]).

4. W. Kroll and F. Skutsch, eds., Matheoseos Libri VIII (Stuttgart: B.G. Teubneri, 1968), II.14, p. 59. “Hi sunt geniturarum ac decretorum IV cardines; quos diligenti semper debemus ratione colligere, ut omnem substantiam fati verissimis pronuntiationibus explicemus” (my translation).

5. For example, see, Bruce S. Eastwood, “Origins and Contents of the Leiden Planetary Configuration (MS Voss. Q.79, FOL. 93v), an Artistic Astronomical Schema of the Early Middle Ages,” Viator 14 (1983), pp. 1-47; Elly Dekker, “Carolingian Planetary Observations: The Case of the Leiden Planetary Configuration,” JHA 38 (2007), pp. 77-90; Richard Mostert and Marco Mostert, “Using Astronomy as an Aid to Dating Manuscripts: The Example of the Leiden Aratea Planetarium”, Quaerendo 20 (1990), pp. 248–61; Anne Lawrence-Mathers, The Magic Books: A History of Enchantment in 20 Extraordinary Manuscripts (New Haven: Yale University Press, 2025).

6. Stephen McCluskey, Astronomies and Cultures in Early Medieval Europe (Cambridge: Cambridge University Press, 1998), p. 147; David Juste, “Neither Observation nor Astronomical Tables: An Alternative Way of Computing the Planetary Longitudes in the Early Western Middle Ages,” in Studies in the History of the Exact Sciences in Honour of David Pingree, ed. by Charles Burnett (Leiden: Brill, 2004), pp. 181-222.