The ancient port of Rome at Ostia had, in legend, been founded by Ancus Martius, the fourth of Rome’s seven semi-legendary kings. However winds magnified by its position and the exposed nature of the mouth of the river proved particularly treacherous, and in the mid first century Claudius established a new and complementary port at Portus, four kilometres (two and a half miles or so) to the north.

Some six decades after Claudius’ port had been begun, a vast hexagonal basin was created slightly inland. This extension was intended to deal both with increased volume in the traffic of goods, and with the significant deposits from the accumulation of sand and mud from the mouth of the Tiber. Trajan’s harbour at Portus is quite simply one of the most extraordinary engineering feats of the Roman world.

Useful sites of places mentioned:

Portus Project

Museum of the Ships at Fiumicino

Harbours of Claudius and Trajan: opening hours and visiting information

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