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.