Recent historical research has thrown up some remarkable connections between the spread of the Black Death in Europe and the cultivation of a kind of grain grown in Central Asia for the last 10,000 years – millet. What’s more, the new research shows that this terrible disease arrived on the fringes of Europe and in the Middle East almost 100 years before the accepted date for its spread throughout Europe. Historian Monica H Green, writing in the latest edition of BBC History Magazine, makes the case that it was millet seed grown in Central Asia that was the primary vector for this terrible pandemic disease. But how and why did this influence the spread of this disease?

First, it should be noted that the latest scholarship involves identifying the specific nature of the disease – Yersinia pestis – that arrived from the east. The genome for this disease has now been fully identified and this has allowed its traces to be identified in humans going back thousands of years. Those existing strains of plague that are most closely related to the Black Death are found in the Tien Shan Mountains and the Djungar Basin – areas that correspond today to parts of Western China and also to Eastern Kazakhstan. It is here that burrow-living marmots still harbour strains of the disease.

Once the genome had been identified, it allowed a kind of family tree of the disease to be built. Although traditionally, the Black Death is said to have arrived in Europe in the 1350s, the latest research, based on the examination of original documents in Arabic, now shows there were outbreaks around 100 years earlier, in the middle of the thirteenth century.

How so? We know that the major event taking place in the middle of the thirteenth century was the arrival of the Mongols, who by this time were concentrating their campaigns on parts of the Middle East, including Syria and Mameluk Egypt. Recent scholarship has now identified plague outbreaks in these regions at this time. The explanation appears to be connected to millet. This humble grain, cultivated for thousands of years in the East, was regarded by the Mongols as a ‘superfood’. A Mongol cavalryman could sustain himself for a day on a cupful of millet, which he would turn into porridge. Throughout their devastating campaigns in the Middle East, including the siege of Baghdad, large Mongol caravan trains were bringing millet from the Tien Shan region across Asia to provision their troops. Soon after, recent research shows that there were outbreaks of the Black Death.

And the explanation? Rodents must have travelled with the millet caravans and it was the fleas on these rodents that spread the disease so efficiently.

After the withdrawal of the Mongol armies from eastern Europe and the Middle East back to their homelands, the disease appears to have died back, with very few cases reported. Only in the 1350s did it return. Again, Dr Green has an explanation. She says that Genoese traders at the city of Kaffa (now Feodosia on the Crimean Peninsula on the Black Sea) began trading with grain merchants in the 1340s, after a long period of trade embargoes. Rather that the apocryphal story of Mongols flinging the carcasses of dead animals over the city walls to infect the residents, she says in was once again rodents living in the grain consignments that were responsible for this new outbreak of the Black Death. The disease itself had lingered in isolated pockets following the initial infection a century before. The Genoans brought the grain back to Italy, where the disease soon reached pandemic proportions throughout Europe in the comparatively well populated towns, with their already established populations of rodents.

So what do we know about the extent of cultivation of millet in the Tien Shan region at the time? In fact, there is quite a lot of evidence. As early as the fourteenth century we have evidence from the Arab traveller and writer Ibn Batuta (1304-1369), who noted that when halting by their watchfires for the night, he was lulled to sleep by the martial songs of the Mongols who, he observed, ate no bread, nor any other solid food, but lived on a kind of porridge made of millet, in which they boiled pieces of meat; he says this was a mode of preparation which was customary with their predecessors – the Scythians, Sarmatians, and Slavonians.

At this time, the city of Kailac was flourishing in the Zhetysu Region of what is now Kazakhstan, close to the banks of the Lepsou River, which flows from the Djungar Alatau Mountains (the foothills of the Tien Shan) towards Lake Balkhash. Perhaps this was one of the cities from which the grain transports were organised towards Europe and the Middle East? From the writings of Thomas Atkinson we know that millet grows all over this region and that there are the ancient remains of extensive irrigation channels in the area.

In his diary for 1849, for example, Thomas Atkinson describes his and Lucy’s journeys through the Djungar Alatau Mountains as they explored the river valleys of this remote region. The Djungar Alatau chain is part of the Tien Shan massif. While the couple were in the valley of the Lepsou River he came across a grain he had not seen before. His diary for 14^th July reads as follows:

“A ride of an hour and a half brought us down into the valley of the Lepsou, a very short distance from the mouth of the gorge in the mountains. At this place it has become a deep and rapid stream and very difficult to cross. Its banks are covered with poplar and birch trees with a great variety of flowering shrubs. The valley is about two versts wide and most of it cultivated by the Kazakhs. Here they grow prasci, a grain used in their cooking instead of rice. It is much like oatmeal, but never used as bread.”

He added that the whole of the Lepsou Valley was irrigated by channels taken from the river at the point where it leaves the mountains. “The Kazakhs are very clever in this branch,” he says. “Some of the channels are carried along the side of the sand hills for probably 60 or 70 versts (40 miles – ed), running up and down the sides of the gullies to keep the proper fall. From these channels hundreds of others are cut and then the whole surface can be kept moist, the only thing required in this climate to ensure a most abundant crop.”

Atkinson mentions at another point in his diary that this grain was widely sown and was watered from many small channels that allowed it to grow luxuriantly. “Another month will make it ripe and then the scene will be changed. There will be many people at work gathering it in with oxen treading out the grain and men throwing it up that the wind may carry away the chaff.”

When I first read this, I was unsure about the identity of ‘prasci’ or ‘prassa’. It turned that prosso is the Russian/Slavic word for a variety of millet – Panicum miliaceum, which is known as Prosso Millet. In Kazakh it is known as tary and is still grown and consumed widely in Kazakhstan, often in the form of a dessert pastry, called zhent, in which it is mixed with butter and honey.

This important grain was first cultivated in northern China 10,000 years ago. It is notable for its very short life cycle – it produces grain only 60 days after planting – and low water requirements. It produces grain more efficiently per unit of moisture than any other grain species and is also very tolerant of high temperatures. Its wild version is common throughout Central Asia and in addition to evidence for its cultivation in north-east China, traces can also be found in Georgia and Germany dating back at least 5,000 years.

Other writers and travellers have also identified millet cultivation in Central Asia. Robert Michell, writing in the Journal of the Royal Geographical Society in 1868 about the Syr-Darya River in Kazakhstan states: “Between these elevations on the North side of the river, where they are more numerous, is the little valley of Aigerik, where the Kirghizes (Kazakhs-ed) sow millet and barley.” The inveterate traveller Henry Lansdell noted in the 1880s that the Kazakhs dammed up mountain streams to water their oats and, especially for the nomads, their millet. The nineteenth century German writer Friedrich von Hellwald observed that millet was grown in the Tarym Basin in Xinjiang, whilst the great Russian explorer Nikolai Przhevalsky noted that “For a more substantial meal the Mongol mixes dry roast millet in his cup and, as a final relish, adds a lump of butter or raw sheep-tail fat (kurdiuk).”

Today millet is regarded as a superfood, rich in both protein and dietary fibre, gluten-free and full of micronutrients such as calcium, iron and phosphorus. But, as we have seen, these qualities were recognised over 800 years ago, when millet helped fuel the expansion of the largest empire in world history – and also brought pandemic calamity to Europe and the Middle East.