Under the weather: Medieval diseases with low mortality and high contagion
As the world is facing a more and more preoccupying, if not straightforward frightening rise in COVID-19 infections, media either encourages us to ‚go medieval‘ (in positive way) to fight the current pandemic, or they draw on historical knowledge with (somewhat forced) parallels to the Black Death. Luckily, it’s not 1347 and the disease many societies will have to cope with in the coming weeks and months is not plague.
Influenza del freddo? A ravaging fever disease in 1357/58
But, in the current situation, looking back in the 14th century is not a waste of time. In early winter 1357/58, the Florentine chronicler Matteo Villani noted a meteorological phenomenon and connected it to a current epidemic:
„From the beginning of winter until the end of January , a gentle weather (air), clear and sunny, persisted without any clouds or winds – very much beyond what is natural. By experience one knew that this weather exterted an influence on all human bodies in the city and the surrounding countryside of Florence, and let them catch a cold. And this poisonous cold stayed in the bodies much longer than usual. And the doctors could not provide a solution from diets and other measures, and many of the persons afflicted died after a long disease. And as spring came close, many died an instant death. The astrologuers said this was because of the influence of constellations, others said because of the subtile air during wintertime.“
Most publications in the history of medicine focussing on the flu will mention that the etymology is from the Italian influenza del freddo, assuming an (astro-)meteorological background to fevers and cold during the cool season. Some publications will even point back to the aforementioned quote from Matteo Villani, although they usually don’t underline that he was not talking about an ‚influence of the cold‘, but an influence of air causing a common cold. But we can hardly be sure what disease it was that Villani talks about here: Is it the flu? Or maybe malaria? The latter seems plausible when we think of the terminology he uses to describe the resurgence of the disease in autumn 1358: „In these times, there was a general disease of long-lasting fevers ([febbre] terzane/quartane) in our land, in Valdelsa and in the Chianti, almost like in the last year, and only few people died. People in the Valdesa and the Chianti wondered about this, as they lived in good and purified air.“
If this 1357/58 epidemic really was flu is hence doubtful, given the considerable mortality Villani mentions for winter 1357/58. Historians of medieval medicine could contribute substantially to research on past flu pandemics, which mostly does not go much earlier than the 19th century and covers even the Early Modern period only superficially. But medievalists, too, could learn from epidemiologists‘ definitions when we might actually think of a supra-regional flu epidemic or even a pandemic.. They have defined five core criteria, which deserve to be quoted in detail:
(I) documentation of a clinical disease characterised by fever and respiratory symptoms, with relatively low population mortality (to exclude more highly fatal epidemic diseases)
(II) evidence of high attack rates across a broad age range
(III) disease must have occurred in at least two geographical regions of the world
(IV) no clear evidence that exposed regions remained unaffected
(V) evidence of explosivity and rapid geographical spread
Supporting evidence would be:
(VI) geographical directionality of spread
(VII) short prevalence intervals (e.g. around six weeks) in major towns
(VIII) higher than expected mortality in the elderly, the young, in pregnant women, and in debilitated persons, and evidence of miscarriages or pre-term deliveries
(IX) evidence of multiple deaths from pulmonary conditions indicative of, or consistent with, pneumonia
The 1357/58 outbreak in Florence is, by what we can actually take from Matteo Villani, not qualifying for criteria (I), (III), (IV) and (V), not to mention the supporting criteria. But the lack of information about – more or less – rapid geographical spread might as well be caused by a lack of source-critical catalogues of epidemic diseases in the Middle Ages. The well-known, yet a bit aged standard reference monograph of Biraben focuses on plague, although there have been raised many doubts that all the diseases mentioned are actually caused by yersinia pestis. And if we take a precise look at Biraben’s plague data, he mentions a cluster of disease outbreaks in 1357 in Italy (4 sources) and Germany (12 sources). If we look more closely at the German sources, we find only very general information about ‚a great pestilence‘ in three sources. This underlines once more that a critical evaluation and compilation of disease information would be a most important aspect of basic research on pandemic diseases that can only be done by medievalists.
But the case of 1357/58 seems hard to understand: There’s no evidence from other parts of Italy that could be interpreted as supra-regional spread of the disease. And mortality is not low enough nor happening fast enough, i.e. within weeks, to let us think of flu. Even if Matteo Villani, a well-informed author with a distinct interest in all aspects of political, economic and civic life in his town and from all other parts of the known world, is quite unique in noting details on a low-mortality epidemics during an age of plague, can we actually expect to find any useful information on contagious, yet not devastating epidemics in medieval sources?
Two more examples from the 14th century
His elder brother Giovanni mentions in his famous ‚Nuova Cronica‘, the most authoritative piece of Florentine historiography in the 14th century, a remarkable event: „In the mentioned year  and in the month of February, there was a general corruption of fever in all of Italy, caused by the cold, and most people felt it, but only few died. The astrologers said that this was caused by the aversion of Mars and Saturn.“ At least a chronological parallel can be found for Paris, where in March 1327 „a great mortality of ill people, poor and rich alike, followed“.
Even more striking is an example four years earlier. It is again Giovanni Villani writing: „In this year 1323, at the end of August and in early September, there was a Western wind (favognano). Because of this, most people in Florence, women and men alike, fell ill with a cold and some days of fever and headaches. And this disease was everywhere in Italy, but few people died of it. But in France, many more died.“ If we look again to France, this is confirmed by an anonymous contemporary chronicler from Paris: „In this year, in summertime, there was in the kingdom of France and especially in Paris a great many of ill people, and many of them died. Everybody was astonished about this.“ A relatively prominent victim might be the nobleman Elzéar de Sabran, serving the Anjou King of Naples on a diplomatic mission and dying of a ‚malign fever‘ on 27 September 1323. There is some chronological confusion, as the chronicle speaks of the peak of the epidemic in summertime, while Elzéar died end of September. So it is hard to tell if the epidemic hit France first and moved then to Italy or the other way round. Going back to Florence, the chronicler Marchionne di Coppo Stefani – actually the pseudonym of a high-ranking, well-informed Florentine statesman, Baldassare Bonaiuti (1336-1385) – provides more precious detail: „It was a common disease of cold, and many were hit with fever, and they lost their appetite, and some – i.e. old men and women – died. This disease was all over Italy, and mid of October it stopped“. And we have another information on fevers in the Mediterranean: The crown prince Alfonso of Aragon put the city of Villa di Chiesa (today: Iglesias) on Sardinia under siege from June/July 1323 to early February 1324. Although the siege was in the end successful and counts as the first step of the Aragonese conquest of this former Pisan island, a Catalan chronicler noted that the attackers suffered from a non-identified epidemic, and that Alfonso himself led the attacks while suffering from severe fevers.
While the 1323 case quite clearly confirms the flu pandemic criteria (I-III) and (V), criterium (IV) seems hard to prove with regard to medieval narrative sources: Given the most incomplete coverage of sources we find for many territories, the absence of evidence is certainly not the evidence of absence. Interestingly, the additional criteria (VII) and (VIII) are fulfilled, too, at least to some extent. And while already the older literature, these mainly uncritical repositories of diseases from the first half of the 19th c., take the 1323-event as the first flu pandemic, they do so without seriously examining what medieval sources – narrative ones and others – can offer. Nor did I have the time to do a thorough research for this small contribution. It would be most interesting to see if we find traces of this flu pandemic arabic or Byzantine sources from other shores of the Mediterranean, but this would need other colleague’s expertise.
This short piece is just a quick reaction to the real-time event that will possibly keep most of us busy in the next weeks or months: following the media, improving our techniques in washing hands and sneezing, wondering (somehow worried) about the most banal symptoms of a cold and slight headaches. Whoever is suffering from a reduced immune system will certainly (and rightfully) be more concerned and careful. Some of the medievalist community might be asked to give interviews on the Black Death, but we’ll be in the happy position to say: It could be much worse (compared to plague and other epidemics with a much higher mortality). We’ll rightfully praise a Venetian innovation of the the 14 century – and might suffer from it, if schools and universities close down or some of us might be advised to go into self-quarantine.
But is this all the medievalist community can do? Shouldn’t we ask ourselves why we haven’t started yet, in the time of big data and rapidly developing digital humanities, a collective Biraben 2.0 project? Sub-communities of the big family of medieval studies have their own, large data collections, as most of the readers will know, so just two examples: One more classical on the history of the Western Emperors with the Regesta Imperii project, or in less establishedf fields like climate history. While it certainly is a work for years and many researchers to assemble, critically check and make available online the wealth of historical disease information we have only for the medieval millenium – why not start to look out for low-mortality high-contagion diseases like the one we are facing right now? The abovementioned examples show that this could be possible. Other disciplines and the public would be most interested.
Feel free to use the commentary function to add something to the presented case studies or express your thoughts about the possibilities of demonstrating, once more, the relevance of medieval studies as proposed above. But most of all: stay healthy.
 Essendo dal cominciamento del verno continovato fino a gennaio un‘ aria sottilissima, chiara e serena, e mantenuta sanza ravolgimento di nuvoli o di venti, oltre all‘ usato naturale modo, per sperienza del fatto si conobbe che da questa aria venne una influenza, che poco meno che tutti i corpi umani della città, e del contado e distretto di Firenze, e delle circustanti vicinanze, fece infreddare, e durare il freddo avelenato ne‘ corpi assai più lungamente che ll‘ usato modo. E per dieta o per altri argomenti che‘ medici [p. 167] sapessono trovare, no potieno avacciare la liberagione, né da quello liberare le loro persone, e molti dopo la lunga malatia ne morivano; e vegnendo apresso la primavera, molti morirono di subitana morte. Dissesi per li astrolaghi che ffu per influenza di costellazioni, altri per troppa sottigliezza d’aria nel tempo della vernata (Matteo Villani : Cronica. Con la continuazione di Filippo Villani, 2 vols, ed. Giuseppe Porta. Parma (Biblioteca di scrittori italiani), here: vol. 2, 166-167)
 In questi tempi fu ne nostro paese in Valdelsa e in Valdarno, di sotto, e nel Chianti, quasi come l’anno dinanzi passato, generali infertà di terzane, e di quartane, e altre febri di lunga malatia, delle quali pochi morivano. Di ciò si maravigliarono le genti di Valdelsa e di Chianti, perché sono in buone arie e purificate, perché due anni l’uno apresso l’altro fossono maculati di simili infermitadi, no conoscendo alcuna singulare cagione di quello accidente (Matteo Villani : Cronica. Con la continuazione di Filippo Villani, 2 vols, ed. Giuseppe Porta. Parma (Biblioteca di scrittori italiani), here: vol. 2, p. 273).
 Jean-Noël Biraben, J.-N. (1976): Les hommes et la peste en France et dans les pays européens et méditerranéens, vol. 1. Paris.
 Ibid, Annexe III, p. 363.
 Ibid., Annexe IV, p. 394. There are no sources indicated for the four Italian outbreaks of disease in 1357.
 Anno predicto facta est magna pestilentia in multibus partibus Rheni et in Hassia et Thuringia et Wedderabia (Chronicon Moguntinum, in: Die Chroniken der mittelrheinischen Städte. Mainz, 2, ed. Karl Hegel. Mainz 1882, pp. 160-161); Mortalitas sive epithuma fuit in dyocesi Spirensi, Babenbergensi, Augustensi, Ratisponensi et eciam in una parte dyoc. Const. in territorio comitum de Wirtenberg circa Stutgarten et Grüningen (Fontes rerum Germanicarum – Geschichtsquellen Deutschlands. 4: Heinricus de Diessenhofen und andere Geschichtsquellen Deutschlands im späteren Mittelalter, ed. J.F. Böhmer, Stuttgart 1868, pp. 16-126, here p. 112); In monasterio Zwiweltun multe persone ex pestilencia hominum morientur (Annales Zwifaltenses, ed. D. Otto Abel and Georg Heinrich Pertz, in: MGH SS 10, Hannover 1852, pp. 52-64, here p. 62).
 Nel detto anno e mese di febbraio fu per tutta Italia una generale corruzione di febbre mossa per freddo, onde i più de le genti ne sentirono, ma pochi ne morirono. Dissono gli astrologhi naturali che di ciò fu cagione l’aversione di Mars e di Saturno (Giovanni Villani : Nuova Cronica, 3 vols., ed. Giuseppe Porta, Parma [Biblioteca di scrittori italiani], here vol. 2, p. 596).
 Et aprez ce [a lunar eclipse on 25 February 1327], à Paris, une très grande mortalité de malades, povres et riches, ensui (Chronique Parisienne anonyme de 1316 à 1339, Hellot (A.) ed., in Memoires de la Société de l’histoire de Paris et de l’Île-de-France, 11, 1884, p. 114). I thank Dr. Thomas Labbé for pointing me to this source.
 Nel detto anno MCCCXXIII, a l’uscità d’agosto e a l’entrar di settembre, fu uno vento a favognano, per lo quale amalorono di freddo con alquanti dì con febbre e dolore di testa la maggiore parte degli uomini e de le femmine in Firenze: e questa pestilenza fu generale per tutte le città d’Italia, ma poca gente ne morì; ma in Francia ne morirono assai (Giovanni Villani : Nuova Cronica, 3 vols., ed. Giuseppe Porta, Parma [Biblioteca di scrittori italiani], here vol. 2, p. 406-407).
 En cest an , en la saison d’esté, par le royaulme de France et especiaulment à Paris, fut si grant multitude de gens maladez, et tant en moururent, que chacun en estoit esbahy (Chronique Parisienne anonyme de 1316 à 1339, Hellot (A.) ed., in Memoires de la Société de l’histoire de Paris et de l’Île-de-France, 11, 1884, p. 90).
 See on the biography of this later (1369) canonized catholic saint: Suzanne Bernard, Les époux vierges: Delphine de Signe et Elzear de Sabran, Editions Perrin, 1994.
 Nel detto anno  e del mese d’agosto e di settembre fu una infermità quasi generale di freddo, ed alquanti pigliava loro la febbre, e perdeano l’appetito, ed alquanti ne morieno, cioè vecchi e vecchie, e fu la detta malattia quasi in tutta Italia, e come venne mezzo ottobre restò (Marchionne Di Coppo Stefani : Cronaca fiorentina des Marchionne di Coppo Stefani, ed. Niccolò Rodolico, Città di Castello [Rerum Italicarum Scriptores, 30/1], here pp. 133-134).
 ma da un altro lato messer lo infante e tutta la sua oste furono colti da tante malattie ch’e’vi perdettero una gran parte dei combattenti, e l’infante stesso se ne trovò malissimo, e fu in gran pericolo di morire, se non fossero state le sollecitudini di madonna l’infanta; per la qual cosa debbe dirsi debitore a Dio e a lei della ricuperata salute. Ma intanto nè medico, nè altro uomo potette persuadere a messer lo infante, quantunque malato, di staccarsi dall‘ assedio; all‘ incontro più volte colla febbre addosso vestiva gli arnesi di guerra e menava i suoi alla pugna (Crónica de Ramon Muntaner , in: Cronache catalane del secolo 13. e 14. Una di Raimondo Muntaner e l’altra di Bernardo D’Esclot, traduzione di Filippo Moisè, Firenze, pp. 55–668, here p. 609).