This jointly authored paper encompasses several contributions which highlight new issues in environmental archaeology and incorporate palaeo-environmental data from preventive excavations. More specifically, it broaches three questions: -The evolution of the environment from the Late Glacial to the present day is analysed using faunal remains (malacofaunae—molluscs, etc.) and botanical remains (pine trunks) preserved in the alluvial deposits of the river Seine; -Riverside occupations based on reconstructions of the hydrography and hydrographic functioning of the channels documented in the Pont-sur-Seine sector and in Bassée; -The marshes assume their full significance within alluvial landscapes occupied or managed by Iron Age and Roman communities. The discovery of a human skeleton is remarkable evidence of specific Latenian (La Tène) practices. The people of Troyes, the Troyens, whose city was constructed in a marsh, had to adapt to the river’s spates and the rising water table. To conclude, the status of the princely Hallstattian site of Vix is re-examined, in relation to the size of the marshes and their location in the landscape; -The matter of the role of climate in cereal production and the dynamics of occupation is examined for the plain of Troyes between 400 BCE and 1000 CE. These approaches underscore that the hydrography and hydrology of the Petite Seine profoundly changed during the Holocene. The course of the Seine today presents a single channel, deep and graded downstream of Troyes, which has made navigation easier since Modern times. This was not previously the case because many channels, which flowed around the gravel domes on which settlements were built, kept the same courses throughout the Holocene. Re-creations of the vegetation and the degree of water saturation of the alluvial soils suggest that the rhythms of flooding have been very different, depending on the recurrence and intensity of spates. If the Seine rarely overflowed during the Neolithic, at least in the Pont-sur-Seine sector, floods seem to have been more frequent during Late Prehistory. What is more, it has been possible to show nothing less than an avulsion (detachment of land) of the Seine in the sector of Vimpelles, which very probably altered navigation, fishing and the spatial organisation of dwellings. The marshy areas were much more extensive in the alluvial plain (sector of Vix, Troyes…) during the Neolithic and Metal Ages. Their ubiquity raises the question of how these areas were used. Lastly, the graph of occupation density for the Troyes plain between 400 BCE and 1000 CE shows no obvious link with climatic parameters. The links between climate and agricultural production on the one hand, and agricultural production and rural settlement density on the other are complicated: the agricultural production of rural areas cannot therefore be deduced just from the calendar of climatic conditions. Finally, if we wish to understand more globally how hunter- gatherer, agro-pastoral and then urban societies developed in the Aube landscape around the Petite Seine, it is necessary to firstly understand on different spatial levels, the way in which the environment has interacted with the economic, political, religious and social systems. These systems all condition the development of societies in the long term. In this light, the findings of the many preventive excavations combined with palaeo-environmental investigations provide the data to write an archaeology of these territories, in an interdisciplinary manner.