Unravelling the complex history of the lost harbour of Pisa

New insights into the evolution and eventual disappearance of Portus Pisanus, the lost harbour of Pisa, are reported in Scientific Reports this week.

The ancient port in a bas-relief on the Tower of Pisa [Credit: Sailko]

Although it has been described as one of Italy’s most influential seaports during the Roman and Middle Ages, little is known about the relationship between Portus Pisanus’s environment and the main stages of its history.

The access area to the Porto Pisano, now completely silted up, near Livorno [Credit: ANSA]

To understand the role that long-term coastal dynamics, sea-level rise and a changing environment played in the harbour’s evolution, David Kaniewski and colleagues reconstructed relative sea levels for the eastern Ligurian Sea over a 10,500-year period. They also coupled historical maps with geological data to reconstruct the morphology of the coast around the Pisa harbour basin.

Roman stone quay and wooden poles, excavation S. Stefano ai Lupi
[Credit: Stefano Genovesi]

They then analysed biological samples from sediment layers to investigate how seawater, freshwater or agricultural activities may have influenced the environment in the area, before comparing and contrasting their data with written sources and archaeological data.

Subsoil sequence analysed in detail [Credit: Veronica Rossi]

The findings suggest that at approximately 200 BC, a naturally protected lagoon with a good connection to the sea developed south of the city of Pisa that would have benefited navigation and trade, and facilitated the establishment of port complexes.

Roman-era seabed, archaeological excavation at S. Stefano ai Lupi [Credit: Stefano Genovesi]

The lagoon 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.

The Meloria tower off the coast of the Pisan Port in 1284 [Credit: Filippo Gini]

It 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.

Source: Nature Eurasia [August 24, 2018]

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