During the Bronze Age, the Upper Seine Valley, in northeastern France, was a dynamic region, at the confluence of two rivers and at the crossroads of two cultural entities. Initially aligned with the Atlantic cultural sphere, the area experienced an increasing influence from the Tumulus culture between the 14th and 11th centuries BCE. This interaction led to significant transformations in material culture and funerary practices, notably with cremations becoming the main rite. To understand the underlying factors behind these changes, the study focuses on human mobility and interactions during this period. Strontium isotope (87Sr/86Sr) analyses were conducted on 100 cremated human bones from eight archaeological sites in the Upper Seine Valley. In parallel, 96 modern plants were analysed to develop a high-density local bioavailable strontium isoscape. The results reveal the presence of two isotopically distinct human groups, each associated with different land-use strategies. While part of the population sourced their food from the southern Yonne river basin, others favoured the Seine-Yonne confluence area, suggesting structured patterns of resource acquisition. In addition, isotopic outliers indicate mobility between these groups, with one case likely reflecting maternal mobility during pregnancy. With a detailed local baseline and a method adapted to cremated remains, this study provides a refined understanding of population dynamics at the end of the Bronze Age. Working within a well-documented archaeological context and focusing on a restricted area enabled a new understanding of land-use dynamics in the Upper Seine Valley during a key period of cultural transition.

The Indo-European languages are among the most widely spoken in the world, yet their early diversification remains contentious1-5. It is widely accepted that the spread of this language family across Europe from the 5th millennium BP correlates with the expansion and diversification of steppe-related genetic ancestry from the onset of the Bronze Age6,7. However, multiple steppe-derived populations co-existed in Europe during this period, and it remains unclear how these populations diverged and which provided the demographic channels for the ancestral forms of the Italic, Celtic, Greek, and Armenian languages8,9. To investigate the ancestral histories of Indo-European-speaking groups in Southern Europe, we sequenced genomes from 314 ancient individuals from the Mediterranean and surrounding regions, spanning from 5,200 BP to 2,100 BP, and co-analysed these with published genome data. We additionally conducted strontium isotope analyses on 224 of these individuals. We find a deep east-west divide of steppe ancestry in Southern Europe during the Bronze Age. Specifically, we show that the arrival of steppe ancestry in Spain, France, and Italy was mediated by Bell Beaker (BB) populations of Western Europe, likely contributing to the emergence of the Italic and Celtic languages. In contrast, Armenian and Greek populations acquired steppe ancestry directly from Yamnaya groups of Eastern Europe. These results are consistent with the linguistic Italo-Celtic10,11 and Graeco-Armenian1,12,13 hypotheses accounting for the origins of most Mediterranean Indo-European languages of Classical Antiquity. Our findings thus align with specific linguistic divergence models for the Indo-European language family while contradicting others. This underlines the power of ancient DNA in uncovering prehistoric diversifications of human populations and language communities.

The Upper Seine Valley sees during the Bronze Age an increase in settlements and cemeteries characterized by a variety of architectures and funerary practices. This variability originates from the coalescence of two cultural traditions, the Atlantic culture from the northwest and the Continental culture from the east, which find its roots in the Upper Rhine area. In this context, our research aims to understand the cultural identity of these communities by reconstructing subsistence economy and palaeodietary patterns and to trace human mobility, which influenced lifestyle and social–economic dynamics. Adding new 10 AMS dating and using multi-isotope (δ 13 C, δ 15 N, δ 34 S) and multi-proxy (botanical, animal and human remains) biochemical investigations, we detected changes in dietary habits throughout the Bronze Age linked to varying C 3 and C 4 plant consumption and diverse animal protein intake by humans. Three main outcomes are highlighted: (1) a variety of farming strategies with different manuring intensity according to the cereal species; (2) site-specific dietary patterns; (3) an increase in millet and animal protein intake during the Late Bronze Age. Moreover, results from one cemetery reveal that individual mobility is more significant for males. These dietary variations, differential agricultural strategies and mobility are consistent with other western Europe research, supporting major global changes in all of Europe at the end of the Bronze Age.

With the first studies dating from the 1990s, France could be seen as being somewhat behind in its research on ancient field systems compared to other countries. Post-war agriculture of north-west France has totally obliterated ancient fossilised landscapes; levelling micro-reliefs and so erasing the smaller irregularities in the landscape such as field systems that in certain cases were laid down more than 4000 years ago. Only since the wide scale development of preventive archaeology during the last 20 years and with its more extensive excavations, has research into prehistoric field systems been possible. This has resulted in the present overview of agricultural boundaries and their chronology from the laying down of the first field systems in the third millennium BCE to their abandonment during the Late Bronze Age. Our aim is not to reconstruct ancient landscapes over large areas – as excavations rarely cover more than 5 ha at a time –but to understand how and why communities took possession of the landscape at the end of the Neolithic and how these planimetric features developed over the following thousand years. This focus is of obvious historic significance, as it targets the monopolisation and the management of the landscape and opens the way to a new reading of Bronze Age societies.