Beached swords from Marano Lagoon (northern Adriatic) reveal ancient land-sea connections and recent coastal evolution

Depositional and erosional processes, subsidence and sea-level changes have strongly modified the coastal landscape of northern Adriatic lagoons. Such rapid transformations have induced significant consequences on human settlements and, thus, on the archaeological visibility of the area, still largely unexplored. We present here six metal swords fortuitously retrieved by fishermen over the last decades in front of the barrier islands of Marano Lagoon (north-eastern Italy). Multi-analytical analyses carried out on the artefacts (X-ray radiography and computed micro-tomography, radiocarbon dating and typo-chronology) combined with the study of the coastal paleo-environment (mainly based on historical cartography and remote sensing) allowed the items' main features to be defined, and highlighted both the historical importance of the area and the significant morphological changes that have occurred there over the last millennium. Data presented indicate that Marano Lagoon was a major hub in the northern Adriatic in the Late Middle Ages, during the crucial period of the Crusades, and in Early Modern times, connecting inland Europe with the Mediterranean Sea. Moreover, the research highlights the onset of coastal erosion that occurred in the last century after a phase of relatively geomorphic stability, possibly deriving from the intensification of human impact and climate change.