The course of the river Neretva opens the path to the central part of eastern Adriatic hinterland for the influences of highly developed civilizations of the Mediterranean. The karst terrain, criss-crossed by mountains and mountain ranges, with a series of larger and smaller units – karst fields, was crucial for the process of forming ethnic communities (Daorsi, Pleraei, Ardiaei, Narensi, Delmatae, etc.). Changes started to occur as early as the 7th century and throughout the 6th century, in the Early Iron Age, when the heterogeneous cultural image of the area by the Neretva river started to change. Influences from the interior, from Glasinac and from the Liburnian, Japodian or Delmatic areas, gradually withdrew or disappeared, and new, more pronounced influences appeared. The reason for this were trade and trade-related activities. Evidence of import from Greece, Macedonia, Epirus and Southern Italy are present in a series of archaeological sites: Grudine in Ukšići (Ljubomir), Gradina hillfort in Prenj near Stolac, Grebnice in Ukšići, Mosko near Bileća, Gradac and Vranjevo Selo near Neum, Pod, Pržine and Mazlumi near Bileća. These are mostly luxury items, prestigious goods, a status symbol for the social elite that was being formed. The processes in question were representative of social stratification – the creation of tribal aristocracy, which, depending on its interests and with the support of an already stratified military class, could have been a factor of integration for close communities in a smaller area or for greater alliances such as those of the Delmatae or Labeatae, and later for socio-political communities of Illyrians – the Illyrian Kingdom, in the southern part of eastern Adriatic coast and hinterland.