What did the Swiss eat during the Bronze Age?

The Bronze Age (2,200 to 800 BC) marked a decisive stage in the technological and economic development of ancient societies. The people who lived at the time faced a series of challenges: changes in the climate, opening of trade and a certain population growth. How did they respond to changes in their diet, especially in Western Switzerland? A team from the University of Geneva (UNIGE), Switzerland, and the Pompeu Fabra University (UPF), in Spain, performed for the first time isotopic analyzes on human and animal skeletons, together with plant remains. The scientists found that the use of manure has spread over time to improve crops in response to population growth. The researchers also found that there was a radical change in eating habits after the introduction of new cereals, such as millet. In fact, the spread of millet reflected the need to adopt new crops after the drought that hit Europe during this period. Finally, the team showed that the resources consumed were mainly land based. The research results are published in the journal PLOS ONE.

Today, archaeological resources for studying the Bronze Age are limited. “This is partly due to changes in funeral rituals,” begins Mireille David-Elbiali, archaeologist at the Laboratory of Archeology and Prehistoric Anthropology at F.-A. Forel Department of the Faculty of Sciences of UNIGE. “People gradually abandoned the practice of burial in favor of cremation, drastically reducing the bone material needed for research. And yet the Bronze Age signals the beginning of today’s societies with the rise of metallurgy.” As the name suggests, societies began to work with bronze, an alloy consisting of copper and tin. “And this development of metallurgy required a more intense trade in order to obtain the essential raw materials. This increased the circulation of traditional handicrafts, prestigious goods, religious concepts and, of course, people between Europe and China ”, continues the archaeologist.

Diet imprinted on bones

The Neolithic Age marked the beginning of livestock and wheat and barley cultivation. But what about diet in the next Bronze Age? Archeobotany and archeozoology have been used routinely to reconstruct the Bronze Age diet, environment, agricultural practices and livestock, but these methods provide only general information. “For the first time, we decided to answer this question precisely by analyzing human and animal skeletons directly. This means that we could study the stable isotopes of the collagen in the bones and teeth that make them up and define their living conditions ”, continues Alessandra Varalli, a researcher in the UPF Department of Human Sciences and the study’s first author. “In fact, we are what we eat,” says Marie Besse, professor at the Laboratory of Archeology and Prehistoric Anthropology at F.-A University. UNIGE Forel Department. Biochemical analyzes of bones and teeth will tell us what types of resources have been consumed. “Forty-one human skeletons, 22 animal skeletons and 30 plant samples from sites in western Switzerland and Haute-Savoie (France) were studied, from the beginning to the end of the Bronze Age.

No differences between men, women and children

The first result of the study showed that there was no difference between the diets of men and women, and that there were no drastic changes in the diet between childhood and adulthood in these individuals. “Therefore, there was no specific strategy to feed children, just as men did not eat more meat or dairy products than women. In addition, when it comes to the origin of the proteins consumed, it has been found that although Western Switzerland is home to a lake and rivers, the diet was based mainly on land animals and plants, excluding fish or other freshwater resources ”, Adds Dr. Varalli. But the study’s main interest is in plants, which reveal social upheavals.

Agriculture adapted to climate change

“During the early Bronze Age (2,200 to 1,500 BC), agriculture was based mainly on barley and wheat, two cereals of origin in the Middle East that have been cultivated since the Neolithic period in Europe”, explains Dr. Varalli. “But since the late Bronze Age (1300 to 800 BC), we have noticed that millet has been introduced, a plant from Asia that grows in a more arid environment.” In addition, nitrogen isotopes revealed that fertilization was used more intensively. “Analysis of various plant species at different stages of the Bronze Age suggests that there has been an increase in soil fertilization over time. This would likely increase the production of agricultural crops.”

These two combined findings seem to confirm the general aridity that prevailed in Europe during this period, which forced agriculture to be adapted; and that there was an intensified trade between different cultures, such as northern Italy or the Danube region, leading to the introduction of millet in Western Switzerland. These new cereals may have played an important role in security of supply and perhaps contributed to the population increase seen in the Late Bronze Age. In fact, these cereals grow faster and are more resistant to drought, at a time when the climate was relatively hot and dry. Finally, the use of fertilizers was accompanied by a general improvement in agricultural and artisanal techniques. “This first study of dietary changes in Western Switzerland during the Bronze Age corroborates what we know about the period. But it also demonstrates the richness of generalized intercultural exchanges ”, says Professor Besse with enthusiasm. We still have a lot to learn about this millennium, despite the scientific problems related to the scarcity of available material. “This is one of the reasons that led me to excavate the Hermit Cave with students from UNIGE. Located in the Piedmont region, in Italy, it is dated to the Middle Bronze Age around 1600 BC ”, concludes Professor Besse.