Amphorae from the Ancient Harbor of Neapolis: Technological and Provenance Insights into North African Trade Connection between the 2nd and 4th centuries CE

Excavations performed during the construction of the underground station in the Municipio square in Napoli revealed the ancient harbor of Neapolis. This key finding has provided precious data for re-enacting trade routes via the study of the material culture and tracing connections among populations. Amphorae associated with the North African trade between the 2nd and 4th centuries CE made the fortune of African products in the Bay of Naples area and, more generally, of the ancient trade between the Campania and North Africa coasts, including Zeugitania and Byzacena (Tunisia), Tripolitania (S Tunisia-W Lybia), and Mauretania Caesarensis (N Algeria). This study examines the definition of the provenance and technology of a set of 31 North African amphorae discovered at the seaport of Neapolis. It integrates a morpho-typological archaeological approach, mineralogical-petrographic techniques, and chemical analyses of the organic residue. Chemical analysis (XRF) indicated a high concentration of CaO in most samples, alongside a homogeneous chemical composition regarding both major oxides and trace elements, with only a few outliers. Polarized light microscopy identified four petrographic groups, which exhibit affinities with the geological features of the suspected production areas and with comparative materials (kiln rejects and reference groups of local ceramics, primarily from the Tunisian coast). Furthermore, the identification of microfossils corroborated the recognition of the raw materials employed. Collectively, these findings offered valuable insights into the association of each sample group with the production ateliers. Pyrotechnological information was obtained by combining mineralogical data (XRPD) and microstructural observation of fresh fractured samples under the SEM. Chemical analyses of the organic residues are in progress using GCMS and proteomic approaches (funded by PNRR PE5 CHANGES (PE00000020), spoke 5) to get clues on traded goods, such as wine and oil, well attested in these types of vessels according to the archaeological literature.