Scientists reveal new insights about the history of lost harbour of Pisa

Scientists have revealed new insights into the evolution and eventual disappearance of Portus Pisanus, the lost harbour of Pisa. Described as one of Italy's most influential seaports during the Middle Ages, little is known about the relationship between Portus Pisanus's environment and its history. Researchers from the University of Exeter in the UK analysed the role that long-term coastal dynamics, sea-level rise and a changing environment played in the harbour's evolution.

They reconstructed relative sea levels for the eastern Ligurian Sea over a 10,500-year period. The team also coupled historical maps with geological data to reconstruct the morphology of the coast around the Pisa harbour basin. The findings, published in the journal Scientific Reports, suggest that around 200 BC, a naturally protected lagoon with a good connection to the sea developed south of the city of Pisa.

The lagoon would have benefited navigation and trade and facilitated the establishment of port complexes, researchers said. It hosted Portus Pisanus well beyond the 5th century AD but its degree of sea connection began to decline from around 1000-1250 AD, as coastlines shifted towards the sea, they said. The lagoon was cut off from the sea and disappeared around 1500 AD when the basin developed into a coastal lake and Portus Pisanus was replaced by the maritime harbour of Livorno.

"Our results underline the importance of such approaches to understand the role of long-term coastal changes and their impacts on the societies living by the sea, notably in the last two millennia," said Matteo Vacchi from the University of Exeter. "The study of the evolution in the coastal zone in the past is a fundamental tool to predict future changes in the context of climatic change," said Vacchi.