Sestertius - Nero AVGVSTI S POR OST C, Tiber and Neptune

This sestertius commemorates the construction of Portus, the artificial harbor Claudius began and Nero completed at the mouth of the Tiber near Ostia. The project was an engineering response to chronic grain shortages that had repeatedly destabilized Rome — the old anchorage at Puteoli was too distant, and storms regularly destroyed grain fleets before they could unload. Nero's formal inauguration of Portus around 64 AD gave him a genuine infrastructural achievement to advertise on bronze, where large flans allowed complex architectural reverses that silver could not accommodate.