Achenheim: a fortified settlement from the last third of the fifth millennium (Bruebach-Oberbergen group) in Lower Alsace

Abstract

Abstract. A preventive excavation carried out in 2016 at the Achenheim Strasse 2 site, west of Strasbourg (Bas-Rhin) investigated part of a ringed village, over an area of one hectare, attributed to the Bruebach-Oberbergen horizon, an Epiroessenian group settled in Lower Alsace between 4400 and 4250 BC. Most of the storage pits discovered belong to this horizon (at least 211 and probably more than 350), and a long section of enclosure outlining a segment of a circle over 155 linear metres followed on from them, consisting of a continuous V-shaped ditch, on average 1.70 metres wide and of equivalent depth. The ditch was probably flanked on the inside by an earthen embankment, as indicated by the asymmetrical profiles of the fillings, and is interrupted twice by openings with structures assimilated to fortified entrances. The construction of the enclosure was carried out as a single project where only the entrances were redeveloped, to varying degrees. The discovery of this enclosure, identified as a defensive structure, marks an important stage in research into regional Neolithic enclosures. Indeed, up until now, such structures were only represented, from the Early Neolithic to the end of the fifth millennium, by ‘Rosheim-type’ monuments, identified by recent research as ceremonial centres. The number of excavations, the large volume of certain storage pits and the surface covered by the enclosure (which we know extends over at least 3 or 4 hectares) suggest that the site hosted a large population. This unprecedented configuration depicts the organisation of the territory and of Bruebach-Oberbergen society in a very different way from reconstructions based on regional sites, which point rather to settlements composed of farms or small scattered hamlets. We examine the historical context that led to the emergence of this large fortified village and propose a correlation with an episode of collective violence that affected Lower Alsace around 4250 BC. This episode is illustrated at Achenheim itself by very specific human deposits with vestiges of warrior rites (victory celebrations). In addition to the important reconstruction of the historical processes at work in the last third of the fifth millennium, the relative abundance of exhumed material from the site also provides the opportunity to better define the stylistic evolution of pottery, to characterise lithic and bone tools, as well as the husbandry system of the Bruebach-Oberbergen group.