Girolamo Manfredi’s Plague Treatise: Individualized Cures and Prevention for the Masses and Elites

Craig Martin

Craig Martin teaches the history of science in the Department of Philosophy and Cultural Heritage at Università Ca’ Foscari Venezia, Italy.

Girolamo Manfredi, Tractatus de peste ([Bologna: Henricus de Colonia, after December 31, 1479]

Francis A. Countway Library of Medicine, Rare Books Ballard 456


A very useful treatise on plague composed by Master Girolamo Manfredi, a citizen of Bologna, and a most worthy physician and astrologer

After we recently satisfied the masses and the unlearned with the vernacular composition of our treatise on epidemics, now the duty remains for us to satisfy the erudite and men of letters by translating the vernacular treatise into Latin. Indeed, many learned men asked us to convert this book—so worthy of the Latin language—since, as they say, they refuse to read vernacular discourses that are suitable for the unlearned. Therefore, wishing to satisfy their requests and desires, we published this book in Latin. And since then, we think it has satisfied everyone.

The proem begins

Since we have repeatedly considered future cruel epidemics that will proceed from the stars into our lower world in the next years—a result of their dreadful constellations—we will say which ones will proceed in this year and in the years to come in our forecasts, and partly we touched upon this in the forecast for this year. Therefore, compelled by a certain piety we composed this very worthy book. First, we wrote in the vernacular language so that its usefulness would be communicated to anyone and now in the literary tongue so that it also illuminates the learned and men of letters. Immediately, great benefit will arise everywhere from this book. Indeed, not one skilled physician has dared to apply himself to curing pestiferous diseases because of the huge dangers of this disease that can occur when visiting men struck by this disease. And only those who are ignorant throw themselves before this danger, and, being empirics, they do not understand the foundations and causes of this disease at all. And they cannot bring cures suitable for them, as the varied nature and complexion of different men demands. Similarly, there is a variety of locations in which the pestiferous abscess arises. But they [the empirics] treat everyone in the same way without any reason [and] completely by chance. Alas, how many people would have escaped from such a very savage disease if they would have duly taken a remedy. Therefore, whoever will have this book with him will be able to provide many treatments. And because of this, many will escape safely if they will carefully observe the teachings of this book that we are writing, along with the suitable cures. People will obtain another certain benefit since we will lay out ways to guard against the epidemic, because there are those who are unable to flee and cannot escape from the pestiferous air.

Thus, we have composed this book that is very useful to everyone. And we pray to God above that in his piety he grants this favor to us so that we are able to bring it forward to completion for the sake of the common good. And consequently, we urge whoever has incurred some benefit from this book not to be reluctant at all to recall Girolamo Manfredi [the author] and pour forth humble prayers to the Lord for him whether he has survived or is hidden among dark shadows.

Accordingly, we divide this book into nine chapters. In the first chapter we will discuss what is an epidemic and we will recount its various definitions among our ancient predecessors. In the second chapter we will inquire into the causes and modes of epidemics and how many causes there are of this illness. In the third chapter we will adduce the signs of plagues that will arise in the near future. In the fourth chapter we will describe the signs that indicate the corruption of air. In the fifth chapter we will show what kinds of people are more at risk of pestiferous disease. In the sixth chapter we will reveal the places that are more disposed to the infection of the air. In the seventh chapter we will define the true signs of a person suffering from this disease even if not afflicted by a pestiferous bubo. In the eighth chapter we will establish how to stay safe from infected air and the contagion of plague with beautiful rules and worthy precepts. In the ninth and last chapter we will set forth remedies for curing patients with pestilence and how to take care of this pernicious illness. With these nine chapters finished, we will come to end of this book of ours. We will follow this method: we will narrate briefly and succinctly what must be narrated about those physicians and astrologers who earlier wrote opinions, just as we will investigate them. And also we will add those things that must be added and we will compose this brief text constructed with great meaning just as we were accustomed to do in other books. And we ask almighty and glorious God for assistance in this undertaking, to whom we give infinite thanks for the so many acts of aid brought to us, such as the ability and inspiration for the composition of this book brought to us by his majesty, whose name may be blessed and exalted throughout the centuries. Amen.

The end of the proem



Girolamo Manfredi finished his Latin treatise on plague before the end of 1479; it was likely printed in the following year. It is a translation of the Italian vernacular version that was completed on December 5, 1478.[1] In 1478, much of Italy was struck by plague, which lingered into the next years killing tens of thousands of people.[2] In addition to Manfredi’s, a number of new plague treatises and older treatises were printed in Italy during those years, including texts by the famous scholastic physician Gentile da Foligno, who died in 1348 during the Black Death, and by the Florentine Platonic philosopher Marsilio Ficino (1433–1499).[3]

From the 1460s until his death in 1493, Manfredi was a prominent intellectual figure in Bologna, where he taught medicine, made public annual astrological forecasts, collaborated with leading scholars, and wrote popularizing works. Born around 1430 in Bologna, Manfredi studied arts in Ferrara and began teaching logic at the University of Bologna, one of the most prestigious universities in Europe at the time. After conducting further studies in medicine, he was awarded a doctorate in that field from the University of Parma. By the middle of the 1460s, Manfredi began teaching medicine, which was typically a better-paid position than teaching philosophy.[4] By the end of the 1460s, he also taught astronomy and astrology. For much of the rest of his life, he annually produced the iudicium, an astrological judgment, and the tacuinum, an astrological handbook that indicated the best days to administer medical treatments like bloodletting, as he alternated between teaching astronomy and medicine.[5] His fame as an astrologer was such that Giovanni Pico della Mirandola in his Disputationes adversus Astrologiam divinatricem, the most important Renaissance polemical writing against astrology, made an example out of Manfredi’s failure to predict the death of Pico’s sister as well as his own death.[6] In accordance with his roles at the university, Manfredi’s conception of medical practice and theory was closely tied to astrology. His use of astrology is among the salient features of his treatise on the plague.

Extant copies of Manfredi’s Latin Treatise on Plague are very rare. This copy is part of a collection of incunabula put together by William Norton Bullard (1853–1931). Bullard (AB 1875, MD 1880 Harvard), a neurologist and pediatrician, amassed a large number of early medical writings that are now part of Countway Library’s holdings of rare books.[7] The vernacular treatise is almost equally rare.[8] The scarcity of these works reflects neither the important roles Manfredi took on as a professor at Bologna nor his success as an author. His Liber de homine (Book on Man) or Il Perché, written in the vernacular and first printed in 1474, explains the causes underlying the preservation of health and prevention of disease. It is in part based on the Aristotelian Problemata.[9] The work subsequently came out in over twenty editions in the early modern period, printed as late as 1678.[10]

Manfredi’s Treatise on Plague reflects the academic culture of Italy and reveals continuities with plague treatises written in the 14th century. The preface points to rivalries among various kinds of healers in Renaissance Italy, where learned physicians trained in scholastic disputations competed with empirics, and where professors like Manfredi emphasized that the mathematical practices of astrologers complement medical theory.[11] The preface contends that the vernacular treatise’s purpose was to educate those who were unable to obtain adequate medical care during the plague because educated physicians refused to visit patients. Consequently, many people were forced to rely on empirics, that is, healers who had not studied at university, whom Manfredi characterized as charlatans, incapable of explaining why their cures supposedly worked and unable to formulate individualized care.

The Latin translation aimed to make these treatments available to an educated audience, which supposedly snobbishly refused to read the vernacular. Written in somewhat stilted Latin prose and filled with technical terms, the treatise contains disputations, which were fundamental to university instruction; numerous citations of authorities such as Avicenna, Aristotle, Gentile da Foligno, and Dino del Garbo (c. 1280–1327); and causal accounts of disease, a hallmark of Galenic medicine. The causes explain the roots of the disease and connect to diagnostic signs and cures for the plague, both generally as well as for specific cases that varied according the complexion or temperament of the individual.

Causes and Signs of Plague

Manfredi defined plague as a “poisonous and contagious disease that is generated in the heart’s vessels by the corruption and putrefaction of the vital spirit,” a view that stems from Galen’s and Avicenna’s ideas about pestilential fever and the heart.[12] Following the Aristotelian Problemata, Manfredi contended that disease was largely spread through corrupt air that enters the mouth and the skin’s pores.[13] He theorized that air is corrupted when putrid vapors commingle with the air’s smallest particles (minimae partes) and infect them.[14] These vapors come from a variety of sources, including from the fumes of fetid swamp water, the sites of earthquakes, and dead bodies.[15] The primary or first cause of these transformations of the elements is found in the position of the stars and planets. Manfredi, holding that changes on earth were necessarily tied to the movements of celestial bodies, posited that eclipses and the conjunction of Saturn and Mars or Saturn and Jupiter posed particular risks.[16] This conviction corresponded to the beliefs of many of his contemporaries and predecessors. For example, both Gentile da Foligno and Marsilio Ficino attributed the plague to the influence of the conjunction of Mars and Saturn, which were maleficent planets according to the prevailing astrological theory.[17] The practical use of the planets for prognostication, however, was fraught with difficulties. Manfredi’s annual judgment for 1478 predicted a “fortunate and good year for Italy.” Despite a conjunction of Mars and Saturn in 1477, he predicted there would not be a great plague from corrupted air in 1478, although he saw signs for one in the following year.[18]

Manfredi believed infected air to be an important vector of plague but not the only one. He also recognized contagion that occurs when one person infected many. Moreover, he thought it was possible that the celestial bodies caused plague directly, that is, without first causing putrefaction in the air or other elements. When constellations caused the plague in this manner, it was less widespread, affecting only people who were vulnerable (subiecti) to the constellation.[19] At times, it infected only one particular house or one person, a fact that Manfredi believed to be confirmed by experience.[20]

Manfredi linked the signs of future plagues to their causes. He had already discussed a few of these signs in Il Perché in passages that address why wet and rainy weather and the sudden appearance of small ash-colored frogs signaled future plagues.[21] In the Treatise on Plague, the signs included fiery appearances in the sky, which signaled the presence of dangerous vapors. Manfredi thought comets were particularly menacing because of Mars’ alleged influence on them. Southerly and easterly winds point to future corruption of the air, as did excessively thick and nebulous air. Animals such as moles and snakes leaving their underground nests indicate that they were fleeing poisons and putrefactions, which are likely to rise into the air.[22] Famines preceded plagues for two reasons: corrupt air harmed crops, and the lack of food rendered people susceptible to epidemics. Finally, eclipses and the conjunction of Jupiter and Mars were identified as astrological signs. According to Manfredi, other constellations are less useful and therefore omitted.[23]

A similar mix of terrestrial and astrological causes explained who was predisposed to plague. The condition of the body and habits greatly affect susceptibility. Broad, open, cutaneous pores permit infected air to enter the body. Excessive humors, heat, and wetness within the body—perhaps caused by frequent sex, a poor diet, or bathing in hot water—promote putrefaction.[24] In Manfredi’s view, these medical explanations are imperfect, and astrology provides a more complete understanding by revealing the relation between individuals’ complexions and the constellation they were born under. These differences were considered crucial to physicians’ ability to make individualized recommendations to patients. Instead of detailing the specifics, however, Manfredi advised that only an astrologer can make these judgments, bolstering his own authority and perhaps even attracting clients.

Cures and Prevention

Manfredi recognized that simply understanding the causes of plague and identifying the signs that predict its arrival were often insufficient to avoid it. In his view, the physician’s first task was to diagnose the disease, for which Manfredi described the symptoms or “true signs” of those ill with plague. He thought that buboes—tumors that gave bubonic plague its name—as well as fevers were the most obvious signs. But since those suffering from the disease do not always exhibit fevers or pustules, less apparent signs were equally if not more useful, in his eyes. Many of these indications related to the fact that, according to Manfredi’s etiology, the plague’s poison attacks the heart. Thus, someone suffering from plague may not be hot to the touch but still suffer internal inflammation. He warned that the patient’s breath might be frequent, belabored, and foul smelling.[25] As the disease progressed, he believed that the pulse often became weak and frequent, while the vital spirit lost its powers.[26] According to Galenic theory, the vital spirit is a subtle substance that the heart uses to control breathing, motion, emotions, and the body’s heat. As the vital spirit weakens, urine is likely to become cloudy, although not always. Other potential symptoms include hiccups, a black and bitter tongue, stomach pains, restlessness, headaches, loss of fear, swelling of the spleen, indigestion, sweats, and tremors.[27]

In order to avoid the plague, Manfredi offered rules that could be applied throughout cities. These rules include burning clothes and linens at the end of the epidemic and throwing out rotten meat and fish. He maintained that removing human and animal waste from the streets helps prevent the infection of the air, as does the swift burial of cadavers, both human and animal. He believed that individuals should protect themselves by improving the air by burning aromatic woods and by eliminating superfluities in the body through bloodletting with the moon in the correct sign. Manfredi recommended various pharmaceutical mixtures of herbs as well as diets to reduce excessive humors. Diet held a prominent place in Renaissance physicians’ set of cures, as they often prescribed moderate consumption of food or drink that they contended would help return the body to a balanced and healthy state.

Aspects of the Copy at Countway Library

Countway Library’s copy of the treatise contains numerous marginal comments. Many mark new sections of the treatise, and there is rubrication throughout. Red ink indicates the beginning of nearly every sentence of the volume. The markings also illustrate what interested the book’s owner or owners. While it might be expected that the most compelling sections would have been Manfredi’s astrological teachings, by far the most intensively marked sections are those that describe remedies intended to assist the heart besieged by the plague’s poison. The first several pages of this section are entirely underlined, headings are given for paragraphs, and marginal notes indicate important points.

The evidently high interest in this section is in spite of a marginal note that links Manfredi’s discussion to Avicenna’s On the Powers of the Heart, a short treatise that typically accompanied printings of Avicenna’s Canon. The note advises consulting Avicenna.[28] The Canon, composed in Arabic in the 10th century and translated into Latin by Gerard of Cremona in the 12th century, was a core textbook in medieval and Renaissance European universities.[29] Its section on “Pestilential Fevers” greatly influenced writers of plague treatises, including Manfredi, who cited it repeatedly.[30] Even if Manfredi’s list of cures is not simple plagiarism, it does bear some resemblance to what is found in On the Powers of the Heart. Among the medications, Manfredi listed simples, mainly herbs and other plant products but also a few minerals such as sapphire and lapis lazuli, which he recommends being compounded into syrups, electuaries, and pills that can comfort, purify, and restore the heart. The lists indicate specific afflictions of the heart that might result from inflammation, excessive cold, or weakened or impure vital spirit. In this way, the proper cure could be matched to an individual patient’s symptoms.

Manfredi also listed medicines for expelling the poison from the heart by an occult power, that is, a power that is not sensible. Here, he enumerated not just simple ingredients but also theriac and Mithridates’ antidote, famous compound medicines of ancient origin that were prepared in pharmacies throughout Europe during the early modern period.[31] Theriac contained a panoply of ingredients, including viper’s flesh, but Manfredi concluded, following Avicenna, that its occult powers originated from the stars.[32]

In addition to prescribing medications, Manfredi advised surgical or manual means to treat the buboes and pustules that often formed on those afflicted by plague. He considered bloodletting to be the primary way of diverting poisonous matter away from the heart. Scarification of pustules was recommended for treating patients’ wounds. He also mentioned a seemingly bizarre yet commonly recommended treatment, namely, placing the “anus of a plucked chicken upon the scarified place,” which would allegedly attract the poison away from the sore.[33] Manfredi considered the death of the chicken during this process a sign of the treatment’s efficacy, as presumably the chicken’s body absorbed the poison.[34] More blandly, cauterization, ointments, and plasters were recommended for buboes, tumors, and pustules.


Manfredi’s treatise had less influence than Marsilio Ficino’s, which was composed in the vernacular in the same years and reprinted several times during the 16th century. Yet there are broad similarities between the two works. Both gave significant roles to the stars, air, vital spirit, and vapors, and both recognized that sensible qualities were insufficient to explain why poisonous vapors affected the heart. [35] Manfredi understood the heart’s functions through the Galenic concept of vital spirit, which Ficino connected to Platonic philosophy.[36] While Manfredi cited weather, animal behavior, and planets as guides to predicting plague, Ficino maintained that in 1477 he had successfully predicted war and plague from the supposed appearance of miracles attributed to relics housed in Volterra associated with Saint Peter.[37] Like Manfredi, Ficino detailed numerous recipes for pills, potions, and plasters, although Ficino seemingly used a greater variety of sources for them than Manfredi did.

 The significance of Manfredi’s treatise largely lies in its attempt to bring scholarly discussions of plague to a broader audience, rather than in any one particular original doctrine. Among the defining characteristics of Manfredi’s work are the replication of scholastic discussions and disputes, the extensive use of Avicenna and the Aristotelian Problemata as authorities, the insistence on air as the main vector of epidemic disease, and the confirmation of astrological influences as an etiological factor and means for predicting which people and regions will be affected by the illness. In this manner, Manfredi gave a causal account of the plague, provided advice about prevention, and put forward individualized treatments correlated to bodily complexion and planetary constellations that empirics were allegedly unable to formulate.


[1] Girolamo Manfredi, Tractato degno & utile de la pestilentia (Bologna: Schriber, [1478], fol. i6v). For a modern edition of both the vernacular and the Latin version, see Girolamo Manfredi, Tractato de la pestilentia. Tractatus de peste, ed. Tommso Duranti (Bologna: CLUEB, 2008).

[2] See the estimates in Andrea Gratiolo, Discorso di peste (Venice: Polo, 1576), 129. He estimated 30,000 deaths in Venice and 20,000 in Brescia. Florence was also greatly afflicted.

[3] Teodoro Katinis, Medicina e filosofia in Marsilio Ficino: il Consilio contro la pestilentia (Roma: Storia e Letteratura, 2007), 95.

[4] For the career path of professors at Bologna, see David A. Lines, “Natural Philosophy in Renaissance Italy: The University of Bologna and the Beginnings of Specialization,” Early Science and Medicine 6 (2001): 267–320.

[5] For his biography, see Anna Laura Trombetti, “Girolamo Manfredi,” Dizionario Biografico degli Italiani 68 (Rome: Treccani, 2007), 698–99. For Manfredi as astrologer, see H. Darrel Rutkin, Sapientia Astrologica: Astrology, Magic and Natural Knowledge, ca. 1250–1800. I Medieval Structures (1250–1500): Conceptual, Institutional, Socio-Political, Theologico-Religious and Cultural (Cham: Springer, 2019), 397–400; Tommaso Duranti, Mai sotto Saturno: Girolamo Manfredi, medico e astrologo (Bologna: CLUEB, 2009).

[6] Giovanni Pico della Mirandola, Disputationes adversus Astrologiam divinatricem, libri I-V, ed. Eugenio Garin (Florence: Vallechi, 1946), (2.9), 164.

[7] James F. Bullard, A Catalogue of Medical Incunabula Contained in the William Norton Bullard Loan Collection: Deposited in the Boston Medical Library (Boston: Merrymount Press, 1929).

[8] Duranti counts 11 extant copies of the vernacular version and 12 of the Latin; see Manfredi, Tractato, ed. Duranti, 2–3.

[9] For the sources of the Il Perché, see David A. Lines, “When is a Translation not a Translation? Girolamo Manfredi’s De homine (1474),” Rivista di storia della filosofia 74 (2019): 287–307.

[10] For a modern edition, see Girolamo Manfredi, Liber de homine: il Perché, ed. Anna Laura Trombetti Budriesi and Fabio Foresti (Bologna: Parma, 1988).

[11] On rivalries between kinds of healers and the medical marketplace in Renaissance Italy, see David Gentilcore, Healers and Healing in Early Modern Italy (Manchester: Manchester University Press, 1998); Katharine Park, Doctors and Medicine in Early Renaissance Florence (Princeton: Princeton University Press, 1985), 85–117; Gianna Pomata, Contracting a Cure: Patients, Healers, and the Law in Early Modern Bologna (Baltimore: Johns Hopkins University Press, 1998).

[12] Manfredi, Tractatus de peste, fol. a2v; Galen, De differentiis febrium 1.7, 7.295–96K; Avicenna, Liber Canonis (Venice: Paganini, 1507), (, fol. 416r.

[13] Manfredi, Tractatus de peste, fol. a2v. [Ps.] Aristotle, Problemata 1.7, 859b15–20.

[14] Manfredi, Tractatus de peste, fol. a4v.

[15] Manfredi, Tractatus de peste, fol. a5r–v.

[16] Manfredi, Tractatus de peste, fol. a5v.

[17] Marsilio Ficino, Il consilio contro la pestilentia (Florence: San Jacopo di Ripoli, 1481), fol. a2r; Gentile da Foligno, Contra pestilentiam consilium (Colle de Val d’Elsa: Bono di Bethuné, 1479), fols. a1v–a2r. Countway Library possesses both volumes.

[18] Girolamo Manfredi, In pronosticon anni saluti MCCCCLXXVIII, MS Munich Bayerische Staatsbibliothek, Clm 647, fols. 130v–131r: “Iste pro Italia fortunatus et bonus foret annus…. In Italia hoc anno non video magnam pestem que est ex aeris corruptione: sed signa et principium maxime et grandis future pestis in anno sequenti.” For bibliographic information and a summary of this forecast, see Alexandre Tur, Hora introitus solis in Arietem: Les prédictions astrologiques annuelles latines dans l’Europe du XVe siècle (1405–1484) (PhD diss., Université d’Orléans, 2018), 693–95.

[19] Manfredi, Tractatus de peste, fol. a6v.

[20] Manfredi, Tractatus de peste, fol. a6v.

[21] Girolamo Manfredi, Opera nova intitulata il perche (Venice: Bascarini, 1553), fol. 61v.

[22] The source for these signs is Avicenna, Liber Canonis, (, fol. 416v.

[23] Manfredi, Tractatus de peste, fol. b4v.

[24] Manfredi, Tractatus de peste, fol. c1r.

[25] Manfredi, Tractatus de peste, fol. c5r.

[26] Manfredi, Tractatus de peste, fol. c5v.

[27] Manfredi, Tractatus de peste, fols. d2r–3r.

[28] Manfredi, Tractatus de peste, fol. c2r: “<de> medicinis cordialibus lege avicennam in libello quod est de viribus cordis.” For a list of editions of On the Powers of the Heart (De viribus cordis), see Dag Nikolaus Hasse, Success and Suppression: Arabic Sciences and Philosophy in the Renaissance (Cambridge: Harvard University Press, 2016), 360–64. Avicenna (d. 1037), or Abū ʿAlī al-Ḥusayn ibn ʿAbdallāh ibn Sīnā, was a leading physician and philosopher who spent much of his life in Persia. For Avicenna’s discussion of medications for the heart, see Avicenna, Libellus de viribus cordis, in Liber Canonis (Venice: Paganini, 1507), fols. 547r–552v.

[29] Nancy G. Siraisi, Avicenna in Renaissance Italy: The Canon and Medical Teaching in Italian Universities after 1500 (Princeton: Princeton University Press, 1987).

[30] Other marginal notes in the Countway’s copy point to the Canon; for example, see Manfredi, Tractatus de peste, fol. e6r: “de his etatibus lege Avi<cennam> quinto canonis de tyriaca.” For Avicenna’s discussion of pestilential fevers, see Liber Canonis, fol. 416r–v. Manfredi cited Avicenna 52 times; see the introduction in Manfredi, Tractato, ed. Duranti, XXVIII.

[31] Manfredi, Tractatus de peste, fol. e4r.

[32] Manfredi, Tractatus de peste, fol. e5v.

[33] Erik Heinrichs, “The Live Chicken Treatment for Buboes,” Bulletin of the History of Medicine 91 (2017): 210–32.

[34] Manfredi, Tractatus de peste, fol. f5v.

[35] Ficino, Il consilio contro la pestilentia, fols. a1r–a2v.

[36] Katinis, Medicina e filosofia, 96–108.

[37] Ficino, Il consilio contro la pestilentia, fol. g2r.