NEW PUBLICATION – A prequel to the Dantean Anomaly: the precipitation seesaw and droughts of 1302 to 1307 in Europe

The cold/wet anomaly of the 1310s (“Dantean Anomaly”) has attracted a lot of attention from scholars, as it is commonly interpreted as a signal of the transition between the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). The huge variability that can be observed during this decade, like the high interannual variability observed in the 1340s, has been highlighted as a side effect of this rapid climatic transition. In this paper, we demonstrate that a multi-seasonal drought of almost 2 years occurred in the Mediterranean between 1302 and 1304, followed by a series of hot, dry summers north of the Alps from 1304 to 1306. We suggest that this outstanding dry anomaly, unique in the 13th and 14th centuries, together with cold anomalies of the 1310s and the 1340s, is part of the climatic shift from the MCA to the LIA. Our reconstruction of the predominant weather patterns of the first decade of the 14th century – based on both documentary and proxy data – identifies multiple European precipitation seesaw events between 1302 and 1307, with similarities to the seesaw conditions which prevailed over continental Europe in 2018. It can be debated to what extent the 1302–1307 period can be compared to what is currently discussed regarding the influence of the phenomenon of Arctic amplification on the increasing frequency of persistent stable weather patterns that have occurred since the late 1980s. Additionally, this paper deals with socioeconomic and cultural responses to drought risks in the Middle Ages as outlined in contemporary sources and provides evidence that there is a significant correlation between pronounced dry seasons and fires that devastated cities.

Bauch, M., Labbé, T., Engel, A., and Seifert, P.: A prequel to the Dantean Anomaly: the precipitation seesaw and droughts of 1302 to 1307 in Europe, Clim. Past, 16, 2343–2358, , 2020

Video lecture M. Bauch: Geoengineering and the Middle Ages

The Berlin-based “Zentrum für Historische Forschungen” of the Polish Academy of Sciences organized, under the lead of Dr. Piotr Filipowski and Dr. Adam Izdebski (Paleo-Science and History, MPI for the Science of Human History, Jena) a series of online lectures with the thoughtprovoking title “What sort of past does the future need?”. Martin Bauch gave a presentation on the topic “Geoengineering and the Middle Ages: Lessons from medieval volcanic eruptions for the Anthropocene”:

CfP for IMC Leeds 2021: Before the Anthropocene – Medieval concepts of interdependent human-nature-relations

Leeds (UK), International Medieval Congress 2021: Climates

Date 5-8 July 2021

Deadline: 20 September 2020

In recent decades, climate history and historical climatology have focused on the economic and social impacts of long-term climatic changes like those which occurred during the Medieval Climate Anomaly or the Little Ice Age. Contemporary worries about global climate patterns have posed new, urgent questions to historians of climate: How did past societies perceive periods of rapid climate change? To what extent were they affected—not only economically, but also in their thinking about the relationship between humans and nature? Traditionally, climate history has focused on reconstruction and impact studies, which implies all too often a one-way relationship: Nature influencing human societies, with humanity merely reacting.

With the emergence of the concept of the Anthropocene, humanity has been recognized as a geological force responsible for fundamental and lasting changes of nature, not least concerning weather conditions via anthropogenic climate change. This raises questions about the degree of reciprocity and interdependence in the relationship between humans and nature. The human ability to reflect about its own agency regarding the course of nature, or the idea that humanity and nature share a common history, have been acknowledged as a postmodern disruption of established explanations of socio-natural relationships (D. Chakrabarty).

However, the distinction between the course of nature and the course of history has been established only since the eighteenth century and recent research made it clear that past societies were already able to think reflexively on their impact on the global environment. Indeed, premodern societies in general and medieval contemporaries in particular, had a very different view: they often assumed that human behavior influenced natural conditions, particularly weather. These assumptions were mediated in religious concepts that crossed into the spheres of politics and economy. Both European and non-European societies accepted the notion that “bad” human actions would backlash in inclement weather while “good” behavior would lead to benevolent conditions. Not only in a Christian context has this relationship often been interpreted by historians rather simplistically as a “retributive theology”. Nevertheless, this cosmological background held much greater social implications, as medieval populations assumed they had a causal influence on weather conditions, and vice versa. A recent example of such an approach has been a new study by Jean-Pierre Devroey on the “righteousness” (droiture) of the Carolingian emperors as a major feature of rulership at that time. Devroey convincingly demonstrates that eighth- and ninth-century thinkers shared a common theory of the “cosmic” dimension of the king that clearly connected good government with the fortune of weather and, consequently, harvests. In the end, he proposes that Carolingian legal-administrative reforms were chronologically connected to bad harvests caused by climate stress and hence constituted a direct political implication of this theoretical background.

The medieval interdependency of humans and nature plays out on at least two different levels: On the one hand, scholars’ written discourses—e.g. treatises, chronicles, letters, and homilies, etc.—give insight into the underlying theories, at least from the point of view of the elites, of the relationship between humanity and nature from Late Antiquity to the end of the Middle Ages in Europe and other parts of the world. On the other hand, sources on economic, infrastructural, and social/institutional history provide information, albeit indirectly, on periods of short-term climate change, as these periods eventually called for specific social adaptation processes. This documentation not only sheds light on the practical reactions of past societies facing abrupt phases of climate change but also enables us to identify underlying theoretical assumptions. Subsequently, this would allow to reconstruct societal adaptions and to examine, at the same time, how specific perceptions of nature shaped these reactions.

To address these issues, we welcome papers dealing with all areas of the globe and from scholars from diverse disciplinary backgrounds. The following questions might serve as possible starting points for paper proposals:

  • To what extent was the interaction between humans and nature—for example, in phases of rapid climate change in the medieval period—truly seen as reciprocal?
  • If the courses of history and nature are not separated in medieval mentalities, to what degree do contemporary witnesses credit natural events with influencing the course of human history?
  • To what extent were natural extreme events used to argue for specific social, economic, religious, and political goals?
  • Was this influence of humans on nature always limited to the context of simple retributive theology, or are other established cultural patterns decisive?
  • Were pragmatic, seemingly modern, i.e. “technocratic” reactions (like institutional reform and infrastructural responses) to natural extreme events in accordance or at odds with religious and cultural discourses?

Thanks to a generous support by our Leipzig-based home institution, the Leibniz Institute for the History and Culture of Eastern Europe (GWZO), we will be able to provide limited funds to reimburse the conference fees and other costs for early career researchers from Eastern and Eastern Central Europe.

A publication of the conference papers is planned. We encourage interested colleagues to submit 300 words abstracts for 20-minute papers by 20 September 2020. Please submit them by e-mail to:

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NEW! T. Labbé: Aux origines des politiques compassionnelles: Émergence de la sensibilité envers les victimes de catastrophes à la fin du Moyen Âge

Read the latest publication of Thomas Labbé on the politics of compassion in the prestigious “Annales”, or enjoy at least the English abstract below before you take a deep dive in your remaining French:

Adopting a socio-anthropological perspective that considers accounts of and reactions to extreme events as social constructs largely determined by sentiments shared and valorized within a given society, this article focuses on the emotions produced by natural disasters between the thirteenth and the sixteenth century. When it comes to the study of catastrophes, historiography has generally privileged the analysis of rational discourse, identifying the secularization of interpretative patterns following the Lisbon earthquake of 1755 as a decisive historical rupture. The emotion-based approach, however, reveals another discontinuity in Western attitudes, which has attracted less attention. Fifteenth- and especially sixteenth-century sources emphasize a new kind of sensitivity toward the “humanitarian” aspect of disasters. Though the interpretive framework remains that of sin and retribution, this shift nevertheless demonstrates an important change in the perception of social distress. First, the language used to describe catastrophes follows a new emotional pattern: over the sixteenth century, notions of terror and pity replace the fear and wonder that characterized medieval narratives. Désastres, a term that also emerged at this time, progressively come to be perceived as tragedies. Second, this new emotional construction is reflected in political theory and practice, as local authorities integrate urgent care for disaster victims into their sphere of responsibility. On a more general level, the article demonstrates the construction of a moral economy that progressively valorized the figure of the victim in perceptions of reality over the fifteenth and sixteenth centuries, planting the seeds of modern compassionate policies.

Labbé, T. (2019). Aux origines des politiques compassionnelles: Émergence de la sensibilité envers les victimes de catastrophes à la fin du Moyen Âge. Annales. Histoire, Sciences Sociales, 74(1), 45-71. doi:10.1017/ahss.2019.139

What to learn from past climate change and epidemics

An interview (in German) with Martin Bauch is dedicated to the topic of what we can learn today from researching past climate change and past epidemic events. The long form is online at (thanks to Sandra Kirchner), a shortened version appeared in the Frankfurter Rundschau on 18 April 2020

That climate history and the history of past pandemics is closely related is also an assumption shared by two colleagues from the US and Israel that have started recently their interesting podcast “Infectious Historians“. Despite the slightly scary name it’s well worth your time.

Medieval weather and diseases in the times of COVID-19

Please have a look at a collateral result from climate historical research published on the Mittelalterblog: You start looking for bad weather 700 years ago, and you end up with indications of a flu pandemic…

Martin Bauch, Under the weather: Medieval diseases with low mortality and high contagion, in: Mittelalter. Interdisziplinäre Forschung und Rezeptionsgeschichte, 9. März 2020,

New Articles from Martin Bauch and Thomas Labbé

Martin Bauch, Gerrit Jasper Schenk (2019). Teleconnections, Correlations, Causalities between Nature and Society? An Introductory Comment on the “Crisis of the Fourteenth Century”

The introductory comment revisits older discussions in medieval studies about the “Crisis of the Fourteenth Century,” connecting it – as recent studies suggest – to a general increase in the intensity and frequency of natural extreme events between the turn of the century and the ravages of the Black Death in mid-century. New approaches to this period of transition examine how societal phenomena coincided with rapid or gradual environmental changes and attempt to establish the relationship between causality and correlation; these methods challenge – albeit without reverting to climatic or environmental determinism – established historiographical paradigms that have tended to explain social facts via other social facts (Durkheim). Hence, the introduction discusses new theoretical tools in environmental history like consilience, resilience, vulnerability, and man-nature-interaction models, such as, for example, those developed by the Vienna School (Winiwarter), but also approaches which have received less attention, like Luhmann’s ecological communication, the Panarchy model (Gunderson/Holling), and Lovelock’s Gaia hypothesis. In the interest of promoting a pragmatic heuristic perspective, the editors expand on the idea of societal teleconnections of meteorological extreme events (Moser/Finzi Hart), as this concept integrates delayed effects and feedback loops, acknowledges spatial crosslinks, and avoids hierarchical impact-levels. Applying the meteorological term “teleconnection” in social historical studies allows for the discovery of “strange parallels” (Lieberman) in the socio-economic development of otherwise unconnected areas of the world, and these synchronicities, in turn, open avenues for the further development of a global pre-modern environmental history.

Martin Bauch, Gerrit Jasper Schenk (2019). Teleconnections, Correlations, Causalities between Nature and Society? An Introductory Comment on the “Crisis of the Fourteenth Century”. In: Martin Bauch, Gerrit Jasper Schenk (Eds.), The Crisis of the 14th Century: Teleconnections between Environmental and Societal Change? (pp. 1–23). Berlin, Boston: De Gruyter.

Thomas Labbé: The Crisis of 1315–1322 in Bresse as Depicted in Manorial Rolls

This paper assesses the severity of the crisis of 1315-1322 in the Bresse region of France. The economic documentation for this region is exceptionally good during the period in which it was under the control of the Duchy of Savoy. The accounts of many castellanies are continuously preserved from the end of the thirteenth century to the fifteenth century, which makes it possible to analyze the potential impact of the Dantean anomaly on the rural economy of this region in full detail. To date, scholars have never studied the impact of the depression of 1315-1322 in this region. This paper presents a classical analysis of four series of manorial rolls (Jasseron, Treffort, Pont d’Ain, and Pont-de-Vaux) for the period of 1300-1330. Particular attention is given to variations in crop yields and vineyard production, as well as to price fluctuations and the indirect demographic evidence that the rolls provide.

Thomas Labbé (2019). The Crisis of 1315–1322 in Bresse as Depicted in Manorial Rolls. In Martin Bauch, Gerrit Jasper Schenk (Eds.), The Crisis of the 14th Century: Teleconnections between Environmental and Societal Change? (pp. 130–152). Berlin, Boston: De Gruyter.

NEW: The Crisis of the 14th Century. Teleconnections between Environmental and Societal Change?

Finally out:

Bauch, Martin; Schenk, Gerrit J. (eds.), The Crisis of the 14th Century. Teleconnections between Environmental and Societal Change?, Berlin; Boston 2019 (Das Mittelalter. Perspektiven mediävistischer Forschung. Beihefte, 13). Open Access here:

Pre-modern critical interactions of nature and society can best be studied during the so-called “Crisis of the 14th Century”. While historiography has long ignored the environmental framing of historcial processes and scientists have over-emphasized nature’s impact on the course of human history, this volume tries to describe the at times complex modes of the late-medieval relationship of man and nature. The idea of ‘teleconnection’, borrowed from the geosciences, describes the influence of atmospheric circulation patterns often over long distances. It seems that there were ‘teleconnections’ in society, too. So this volumes aims to examine man-environment interactions mainly in the 14th century from all over Europe and beyond. It integrates contributions from different disciplines on impact, perception and reaction of environmental change and natural extreme events on late Medieval societies. For humanists from all historical disciplines it offers an approach how to integrate written and even scientific evidence on environmental change in established and new fields of historical research. For scientists it demonstrates the contributions scholars from the humanities can provide for discussion on past environmental changes


St. Mary Magdalene’s Flood (1342) at the Intersection of Environmental History and the History of Infrastructures: A Compound Event as a Catalyst of Medieval Infrastructure Development and Public Welfare

Reconstruction of the flood wave in July 1342 for the Main basin. Destroyed bridges in red. Map: Martin Bauch Quelle: Wikimedia Commons: CC BY-SA 3.0)

This recently published  article (in German) sheds new light on the disastrous event of St Mary Magdalene’s Flood in Central Europe in 1342, which scholars have thus far largely neglected, by examining administrative documents like charters and accounts for the first time, while also considering scientific proxy data like precipitation reconstructions based on tree rings. The result is a much more nuanced reconstruction of these two years that included extreme flooding (in February and July 1342 and July 1343), but also pronounced dryness in spring 1342, which might explain the extreme erosion events geomorphologists attribute to the strong precipitation of these years. The events of 1342/43 are a good example of how a pre-modern, multi-factorial compound event could have disastrous consequences when natural extreme events and disadvantageous socio-economic conditions coincided. Examining a wider variety of written sources reveals that the supra-regional dearth and famine in Central Europe was linked to the fact that the flood occured before grain could be harvested in 1342. Furthermore, the article focuses on infrastructural adaptions like changes in bridge design or large water-infrastructures, as well as on normative reactions at a regional or local level that can be understood, at least partially, to have been caused by the flood disaster. These processes of technological and normative adaption can be understood, on the one hand, as second-order-perceptions of nature in Luhmann’s sense; on the other hand, they illustrate the importance of natural extreme events as a catalyst for pre-modern development of infrastruture. In the aftermath of 1342/43, areas to the north of the Alps implemented flood-protection measures to protect the public welfare for the first time, at least such initiatives that went beyond local responses to involve regional and supra-regional powers up to and including the Holy Roman Emperor.

Balduin Bridge over the river Mosel in Koblenz, built in 1341 to 1358 – and most possibly hit (and influenced in its design) by the flood events of 1342/43. Source: Wikimedia Commons, public domain.

Full article (in German) – read only version here.

Bauch, Martin, Die Magdalenenflut 1342 am Schnittpunkt von Umwelt- und Infrastrukturgeschichte: Ein compound event als Taktgeber für mittelalterliche Infrastrukturentwicklung und Daseinsvorsorge, in: NTM. Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin 27/3 (2019), S. 273-309.

Grape Harvest Dates from Burgundy demonstrate (once more) Global Warming since the End of the 20th Century


Organisation of the harvest in 1487; page from the accounting book of the Church of Notre-Dame of Beaune (Archives départementales de la Côte d’Or, B 2918/109)

Records of grape harvest dates (GHD) are the oldest and the longest continuous phenological data in Europe. They have been repeatedly used since the end of the 19th century to reconstruct past climate variations, and in the two last decades to reconstruct spring-summer temperature beyond the instrumental period. Newly, the GHD from the famous vine region of Beaune (Burgundy) between 1354 and 2018 have been entirely drawn from the archives and published in the European Geoscience Union journal Climate of the Past. It constitutes the worldwide longest GHD series in the literature and one of the longest phenological records ever. The 664-year-long Beaune series has been cross-checked with the April-to-August Paris temperature series comprising the 360 years from 1659 to 2018 (R = -0,76), as well as with tree-ring series, with documentary proxy evidence and with the Central European temperature series (from 1500). Statistical models show that the series is very reliable to reconstruct April-to-August temperature in the long run. Of major interest, the series is clearly subdivided into two parts. From 1354 to 1987 grapes were on average picked from 28 September on, whereby during the last 31-year long period of rapid warming from 1988 to 2018 harvests began 13 days earlier. The 33 earlier harvest dates of series are unevenly distributed over time. 26 of them occurred between 1393 and 2002, whereby since the hot summer 2003, 8 out of 16 spring-summer periods were outstanding according to the statistic of the last 664 years. In the Paris temperature measurements since 1659, April-to-July temperature reached the highest value ever in 2018. In sum, the 664-year-long Beaune GHD series demonstrates that outstanding hot and dry years in the past were outliers, whereby they became the norm since the transition to rapid warming in 1988.

Beaune GHD time-series, with indication of the 33 earlier dates (Labbe et al. 2019, p. 1496).

To know more: Labbé, T., Pfister, C., Brönnimann, S., Rousseau, D., Franke, J., Bois, B.: The longest homogeneous series of grape harvest dates, Beaune 1354-2018, and its significance for the understanding of past and present climate, Climate of the Past, 15, 1485-1501,, 2019.

Find here a podcast interview with Thomas Labbé (in German) by

Falcons in the Territory of the Teutonic Order and the Duchy of Prussia

by Marie-Luise Heckmann (University of Potsdam) with the assistance of Dieter Heckmann (Secret State Archive of Prussian Cultural Heritage, Berlin)

Old-French translation of Emperor Frederick II’s ‘De arte venandi cum avibus’, depicting falcons given as a present to a ruler, Bruges around 1482. Source: Wikimedia commons, public domain

The present article addresses the topic of “Falcons in the Orderland and Duchy of Prussia” in regard to the interplay between humans and animals. The hawks (i.e. peregrine, gyrfalcon) serve as climate indicators on the one hand, and as examples for the price of rank and status in the political game of power on the other hand. Depending on the respective onset of winter, they turn out to be ecologically and economically scarce, which caused a need to budget

The ecological costs of falconry and the export of hawks of the Prussian rulers can be quantified with the respective weather and the resulting number of hawks, which arrived between late August and mid-December in Old Prussia. The lack of animals and the annual dates of bird migration resulted mainly from the weather phenomena on the Kola Peninsula in June, July and August of each year. The Fennoscandian climate is likely – as it is today – to have alternated with the weather in Central Europe. Frostbursts and gusty winds in summer on the Kola peninsula were probably associated with frequent northwest current high-pressure conditions in central Europe, as a rainy summer in Central Europe often correlates with a significant decline in falcons in the following autumn.

The beginning of winter, and here the hawks prove to be climate indicators, was indicated by their departure as soon as the water began to freeze. The pivotal point of this article is: The earlier winter began, the earlier the falcons left Prussia, Lithuania and Livonia. The onset of winter, looking at the falcon’s catching dates, moved from the end of the 14th century to the second third of the 16th century on average by about four weeks, from the third week of November to the third week of October. The reason for this was evidently the beginning of the Little Ice Age.

The regional fishing dates also show hawks migrating in the wake of their prey – small and medium-sized birds – from the inland lakes and rivers, where they arrived in late summer, to the Baltic Sea coast, which they left at the onset of winter. For a particularly long time, the mild climate of the Curonian Spit influenced by the effects of the Gulf Stream (long hours of sunshine, warm water) allowed the hawks to find food. Thus, the falcon in Prussia can provide basic knowledge about the historical migration of birds before the age of ringing.

Hawks have been investigated for Prussia mainly in terms of hunting, catching and killing, as well as princely gifts and diplomatic exchanges. The Great “Marienburger Tresslerbuch” (a special account book, 1398-1409) allows not only important insights into the scope and costs, but also into the methods of falcon-catching and the addressee of the falcon gifts of the Grand Master respective the Duke in Prussia. The falcon letters, several falcon lists and individual contracts with falconers, which are quite often used since the end of the 14th century, make it possible to limit the fishing times, as well as to reconstruct the falconers’ travel routes to Western and Central Europe.

The economic costs of politically-diplomatically motivated Hawk gifts for Western and Central European princes included the catch premiums and the travel,  and subsistence costs of the falconer and his animals. In Mark Prussian, they were in the lower to middle double digits and can be seen as a contribution to peacekeeping, for timely information and for the (occasional) participation in the political power game of their time. In other words, a hawk for the French king is just a fifth to a quarter as much as a stallion for the battle.

In Preparation in Polish: Sokoły w państwie krzyżackim i księstwie pruskim – rzadkie dobro ekologiczne i ekonomiczne, in Człowiek – Klimat – Przyroda. Perspektywa antropocentryczna [Man, climate, nature. An anthropocentric perspective], ed. Piotr Oliński / Wojciech Piasek, Toruń.

Already published in German: Falken im Ordensland und Herzogtum Preußen – ein ökologisch und ökonomisch knappes Gut, in Jahrbuch Preußenland 8 (2017), pp 7-40.

Contextualizing Drought in Medieval Italy: A Case-study of the 1302-1304 Events in Siena

by Martin Bauch

Dendrodata seems to be the most reliable way to reconstruct past periods of drought. But as this post tries to argue, in case when we have a lot of written sources and only a minor number of dendrochronological sites available – as it is the case in Italy for most of the period before 1500 -, seemingly precise dendro-reconstructions can hide more of past realities than they reveal. Furthermore, the societal consequences of drought remain completely a task to be explored by medieval climate history.

Dendrochronological evidence: No drought in Italy?

No signs of a lack of precipitation in Italy in the years 1302-1304 are visible in the Old World Drought Atlas. But this reconstruction – for the time in question – is based on only four datapoints, two in the Italian Alps, two in Calabria. On the contrary, various data points available on the drought in Western and Central Europe in 1304-1306 correspond perfectly with textual evidence

Documentary evidence: A chronology of drought in 1302-1303

In spring 1302 we find the last evidence of strong precipitation, but from summer 1302 onwards we have reports of a complete lack of rain for up to 13 months in Northern Italy and Tuscany; the most detailed reports come from Parma and Siena. The winter of 1302/03 is said to be particularly cold in Tuscany, Verona and Friuli, the river Adige freezes over. The summer of 1303 remains dry, only one short episode of strong rain in Tuscany is known. In 1304, precipitation sets in again with force, inundating Tuscany, showing torrential rainfall in the Po valley and blanketing the Friuli region in deep snow. Documentary evidence from narrative sources for the drought in 1302/1303 is not as overwhelming as we might wish – but an examination of administrative sources (see ‚Reactions in Siena‘) and to its potential impact (see below) renders a clearer picture.

Societal impact of the 1302-1303 drought in Italy

From narrative sources, i.e. contemporary chronicles, a number of general impacts of the drought event can be reconstructed for different cities in Northern and Central Italy.

Dearth: A general shortage of foodstuffs, mainly grain, is reported in Perugia, Siena, Florence, Lucca and north of the Apennine mountains in Bologna, Parma and Ferrara.

Grain importation: Chronicles mention successful grain imports ordered by the cities of Venice, Bologna, Florence and Siena. Ferrara fails to obtain the urgently needed cereals.

Failure of infrastructures: Water mills are falling dry, according to reports from Bologna and Parma, but also from the hinterland of Siena. This causes further financial burdens for the cities, as the mills contribute a considerable sum to the overall budget of the communes. Irrigation proves vital to make the seeds sprout – in Parma, a huge new well is constructed in 1304 to improve access to water.

Cultural reactions: From the area of Lucca we know of organized prayers and processions in local churches for rain.

City fires: Studies for the early modern period and especially for the drought of 1540 in Central Europe have argued convincingly that city fires are more frequent after longer periods of abnormally low precipitation, as roofs and wooden structures become more vulnerable to ignition.

We find a remarkable series of city fires between 1302 and 1304 in Italy: a smaller fire in Siena already in 1302, then fires in very different parts of Italy including Asti in Piemont in1303 as well as Cividale in Friuli in 1303 and 1304. But the most remarkable city fire strikes in Florence in June 1304:
The so-called „Great Fire“ started accidentally in the wooden granary of Orsanmichele and was said to have destroyed almost 2,000 houses. Strong winds made any attempts to fight the fire useless. Some authors accuse the Florentine White Guelphs of arson and having caused one of the largest disasters in Florentine history; the aftermath of the fire was characterized by political persecutions of oppositional groups. Beyond that, in the years after the event, the first organized squads of firefighters were installed in every quarter, supervised by the Uffico del Fuoco. The only depiction of the event is from the Nuova Cronica, Giovanni Villani (BAV, Ms. Chigiano LVII 296).


Siena facing the drought of 1302-1303

Archival sources from the State Archives in Siena provide a more detailed picture of communal reactions to the extended drought from summer 1302 until summer 1303. Regular precipitation set in as late as spring 1304. The protocols of the Consiglio Generale, the city‘s main council that met every 7-14 days, are an excellent source for tracing communal government‘s perception of the dangers and the measures taken to overcome the crisis.

Grain importations
When dearth set in Siena and Florence early as 1302, the port of Talamone, 100 km south on the Tyrrhenian Sea, was used for the first time to import larger quantities of grain both for Siena and for Florence. Siena allowed Florentine grain to be transported across its territory. But the food shortages continued, and already in March 1303, the Consiglio Generale debated the topic of grain imports once more, allowing them to enter the Sienese territory via Talamone, Grosseto and Porto Ercole – none of which were under direct political/military control of Siena at the time.

Grain management policies and forced loans
An elaborated grain management policy, called the Divieto, developed since the middle of the 13th century during several food crises, was activated in 1303. It allowed Sienese officials to confiscate grain from Florentine traders as they crossed Sienese territory in the spring of 1303. In May 1303 they complained to the Sienese Consiglio Generale about this. But the situation got worse during the summer of 1303, and on 27 July the city council adopted a forced loan of 18,000 Sienese pounds – roughly one third of the city‘s annual budget – that had to be extended by a number of wealthy citizens. The money was explicitly meant to buy grain or pay for grain that had already been ordered.

Improving water infrastructure
Siena always lacked water because the city was constructed on several hills and had no larger natural rivers nearby. Starting in the 11th century, a sophisticated system of wells and artificial water tunnels (bottini), totaling a length of 25km, secured the city‘s access to potable water. In the first decade of the 14th century, some substantial new fountains were built in the city, possibly a reaction to the drought of 1302-1303.

For centuries Siena‘s inhabitants were convinced that a large subterranean river – the so-called Diana – was running below the rocky hills of their city. The communal governments repeatedly searched for this river in the High Middle Ages, and for the last time in the first two decades of the 14th century. It‘s quite plausible that this happened in the first decade of the century, as Dante Alighieri in his Divine Comedy, finished in the early 1310s, referred ironically to the Sienese searching once more in vain for their mythological river:

«Tu li vedrai tra quella gente vana / che spera in Talamone, e perderagli / più di speranza ch’a trovar la Diana; / ma più vi perderanno li ammiragli. »
– Dante, Purgatorio, Canto XIII

Veduta of a City by the sea, probably Talamone, by Ambrogio Lorenzetti (1290-1348) [Pinacoteca Nazionale, Siena]. Source: Wikimedia Commons, public domain.
(You will find them amongst the foolish crowd / who put their trust in Talamone, and will loose / more hope there than in their search for Diana. / But there the admirals will loose the most.)

This interpretation is all the more plausible as Dante connects the search for the Diana with the acquisition of the port of Talamone that took place in 1303.

Improving trade and transport infrastructure

On 10 September 1303, the Consiglio Generale decided to buy the aforementioned port from the Monastery of San Salvatore on the Monte Amiato – a plan discussed since 1293. In 1304 to 1306, Siena invested considerable sums to expand the small harbour into a proper trade port designed for importing grain and salt. Siena had no ambitions to become a naval power or a need to export its (minor) goods overseas. So recent research disagrees with Dante‘s interpretation above: Buying Talamone was a clever move to improve food security in the future, as one can see in the next substantial food shortage during the 1310s, when Siena had permanent access to naval grain trade.
The small port was important enough for Sienese self-conception to be portrayed in the idealized and programmatic landscape from the fresco on the „Effects of Good Government“ in the Palazzo Comunale of Siena from 1338 by Ambrogio Lorenzetti, where the city‘s ruling elite depicted all of its successes. It even shows grain traders crossing the red stone bridge in the lower right corner. The open sea on the fresco was transformed into a land-locked lake around 1430, when malaria and paludification had turned Talamone into a worthless financial burden for Siena.

The Sienese countryside as depicted in the frescoes of the Buon Governo by Ambrogio Lorenzetti. The port of Talamone enlarged and the former coastline changed to an inland lake around 1430. Source: Wikimedia Commons, public domain. Changes by Martin Bauch.


The drought of 1302-1303 (maybe 1304) all over Italy is traceable best in documentary evidence, while dendrochronological data is misleading due to its scarcity. The societal impact can be reconstructed both from narrative and administrative sources: Part of its consequences, like dearth, grain importation/management and impact on water infrastructures like mills are comparable to what is caused by continuous rain and floodings; other aspects like an increased probability of city fires and improved water infrastructures like wells and aqueducts are characteristic only for dearths. The push for easier access to long-distance grain trade via political control over seaports are maybe the most important long-term effects, and similar developments can be found for any natural extreme event threatening food security in the Italian Middle Ages.

This information is taken from a poster given by the author during Session  32 (Large-scale hydroclimate variability and change of the Common Era: Patterns, Impacts, and Processes), 5th Open Science Meeting. PAGES, Zaragoza, 11 May 2017.  Available for download here.

Europe, 1137 AD: Drought, fires and thirst

by Thomas Labbé

The summer of 2018 broke a new record on the thermometer. Temperatures reached more than 30°C at the polar circle, and a large part of the northern hemisphere has been struck by a drought that brings back in memory of everybody the summer of 2003.

In the memory of climate historians, the summer of 2018 would automatically refer to the summer 1540[1] which has been assessed as one of the major droughts of the millennium at the European scale. Less known is the dryness that affected North-West of Europe in 1137. Although we don’t know much about this event, the sources clearly state that something unusual had happened. Richard of Poitiers, a Cluniac monk, wrote for example in his chronicle that rivers, fountains and lakes dried up. Even more worrying for him were the fires that broke out from the bowels of the earth and no rains could extinguish them!

Fuit tanta siccitas in Gallia, quanta retroactis saeculis in eadem regione unquam visa est aut audita, ita ut fontes et flumina, lacus, putei etiam siccarentur. Visus est etim ignis biennio cremare super terram, qui casu aut sponte missus per rimas arentis terrae in imis ceciderat, nec frigor, nec gelu seu imbribus extingui poterat[2].

A remarkable set of monastic chronicles refers to the drought of 1137. In his overview of climate-related narratives in medieval Europe, Pierre Alexandre found at least 14 different contemporary sources that mentioned the event, in an area covering south-west France to Netherlands[3]. Chroniclers give only short descriptions of it, but they generally agreed that it lasted from March to September of this year. Orderic Vital, a monk of Saint-Evroult in Normandy, adds that the temperatures reached a continuous peak in July and August. People suffered from thirst, especially during the summer labour in the fields, and as many water bodies in the region were dry, peasants had to make long walks under the heatwave to get some water. Interestingly enough, chroniclers mostly emphasized the vulnerability of the population to thirst on the one hand, and the risk of fire on the other hand. Surely, the aforementioned strange story reported by Richard of Poitiers is a metaphor of the multiplication of fires that occurred in relation with the drought.

Fig. 1. Map: Thomas Labbé.

A close look at the history of architecture gives actually some more details about the extent of the drought. In 1137, church and city fires really occurred throughout a large part of Western Europe. They shape a region that roughly overlaps the area documented by the chronicles. It is thus more than probable that these fires occurred because of the drought. For example, the cathedral of Rochester burnt in June 1137, as well as the cathedral of York. In Germany, the cathedrals of Mainz and Speyer burnt in the same vintage, when in France, fires destroyed the city of Dijon in the end of June, and the city of Amiens in the beginning of August.

Finally, the pattern that we can draw with the sources at our disposal is that this little known event certainly constitutes one of the major droughts of the Medieval Climate Anomaly (MCA), the so-called warm period of the central Middle Ages. From the documentary sources, its extension covered at least England, Netherlands, Belgium, West Germany and a large part of France, where the heatwave lasted continuously in July and August (fig. 1). If we believe the dendrological data provided by the Old World Drought Atlas, the South of Scandinavia has been affected, too (fig. 2) , so this was definitely a European scale event.

Fig. 2: Dendrological data for 1137. Source: Ed Cook et al. 2015, OWDA.

[1] Wetter O., Pfister Chr., et al., “The year-long unprecedented European heat and drought of 1540 – a worst case”, Climatic Change, 125, p. 349-363.

[2] Ex chronico Richardi Pictaviensis monachi cluniacensis, Recueil des historiens des Gaules et de la France, 12, Paris, 1877, p. 415.

[3] Pierre Alexandre, Le climat en Europe au Moyen Âge: contribution à l’histoire des variations climatiques de 1000 à 1425 d’après les sources narratives de l’Europe occidentale, Paris, EHESS, 1987.