Modélisation des interactions en Italie du Nord au premier âge du Fer : de la circulation de parures aux réseaux d’influences culturelles = Modelling interactions in Northern Italy during the Early Iron Age: from the circulation of ornaments to networks of cultural influence

In traditional approaches based on written sources, most often posthumous and reflecting an external point of view (etic), Italian archaeological cultures are often defined as autonomous entities (peoples), characterized by specific productions and sharing clearly established geographical boundaries. Within the framework of the ANRJC Itineris (https://itineris.huma-num.fr/), focusing on the study of craft practices in north-western Italy during the first Iron Age, the critical re-examination of the documentation and the analysis of new data allows us to approach the interactions between cultural entities from another angle, going beyond the dichotomous and hierarchical interpretation of centre-periphery, and thus to be able to interpret the phenomena of cultural interactions between so-called marginal entities through a modelling of the archaeological data. This paper therefore proposes to re-examine the roles of italic populations described as peripheral within the networks of interaction and technocultural transfers that developed in the early Iron Age in northwestern Italy. By applying statistical and spatial data modelling (R program and Graph theory), it is possible to visualise and order complex and heterogeneous data, such as archaeological records, as well as to identify a dynamic typology of connected networks and sub-network. The selected data set includes more than 2000 copper-based alloy objects, mainly ornaments and the waste products associated with their production, from both settlements and funerary contexts, well documented and located in southern Piedmont (indigenous communities in Inner Liguria) and western Emilia (indigenous communities in the western sector of the Po valley). By applying statistical models (R programming and network analysis), the aim was to be able to examine and classify this complex and heterogeneous data, in order to identify a first dynamic typology of connected networks and sub-networks, linking neighbouring entities and major cultural areas according to variable geometries. This data set, which has recently been published and revised, has been structured on the basis of hierarchical descriptors, and its characterization (typology, context and quantification) has been completed by adding a qualitative variable, here called 'style'. The role of this factor, based on the morphostylistic study of each object, is to translate into factual terms the local tastes/adaptations of supra-regional models and types, thus making it possible to model the relationships of cultural influence between communities. The modeling, based on graph theory and the application of community detection algorithms (here edge.betweenness.community, from 'igraph' R package) enables the degree of importance and proximity between groups to be assessed by hierarchical segmentation of links, in order to identify coherent clusters. By breaking the links between sub-groups of nodes, we can identify groups of nodes that share more with each other than they share with the other nodes in the graph (communities of attributes). Applied for each period, this segmentation is represented on a map by assigning the color of the groups (clusters) to the sites, thus facilitating spatial reading and geographical interpretation of the results. The visual analysis of the graph, or the statistical analysis of the network, is in fact both a model and a powerful formalism, but it is no substitute for the archaeological and historical interpretation of the data. This approach has highlighted the major role played by fibulae as the most widely adopted and adapted item of clothing and ornament, in terms of morphology, style and technique. Nevertheless, their widespread occurrence across the whole of northern Italy ultimately masked the identification and circulation of more specific connections, raising the issue of the use of this marker as a key indicator of mobility or cultural identity. While the influence of Golasecca is attested throughout the period under consideration here, more localised interactions based on specific classes of objects reveal a sophisticated interplay of influences that reflects relationships with variable geometry, never unambiguous or unidirectional, and where local production, adaptation, creativity and imports describe social realities on the move and of growing complexity. Starting from this point of view, the comparative study of clothing item types and styles has allowed us to explore more deeply their interactions, clarifying, by the same way, the impact of their dissemination in a medium scale: Northern Italy. Highlighting these dynamic, non-exclusive links based on creativity and adaptation, rather than on predefined geographical or cultural boundaries, illustrates how these boundaries are socially negotiated and dynamically recomposed over time, defying the traditional, unidirectional perception of a hierarchical structure of dependence between center and periphery. The goal is to produce operational distinctions between local productions, imports, imitations, and local transformations. By modelling the fashion tradition through the analysis of shared clothing items, this paper would like to propose a critical review of the markers of cultural identity, mobility, interaction traditionally used looking for alternative theoretical interpretation and social narrative of the role of indigenous communities in the North Italic trade et craft activities.