Ancient Portus (near Ostia), Rome’s imperial harbor

Portus commented by Braun

“The two ports situated near Ostia and shown here in plan view from an elevated position are believed to have been built by two different Emperors: namely that the larger egg-shaped one was built by Emperor Claudius; the adjacent, smaller hexgonal one, however, by the Emperor Trajan […]. The arm of the Tiber, which was dug by the ancient Romans for unloading goods brought into and sent out of the port, is approximately eight or ten ells across. The Tiber, on the other hand, measures 40 ells at its mouth, where the city of Ostia was built by Ancus Marcius, the fourth king of the Romans. So esteemed was it by the ancient Romans, although its climate is unhealthy, that it was exempt from usual taxes and duties.”

TRANSLATION OF CAPTION: Description of both harbours in Ostia, from the little book on the seas by Horatius Tigrinus.

Taschen on Portus

This is a bird’s-eye view from the north across the port of Portus, whose structure with the two basins, the mole in front and the colossal statue known from visual and literary sources has been reconstructed with astonishing accuracy. The spolia on the upper margin of the illustration refer to ancient Ostia. The first basin, the outer harbor, was laid out about 3 km north of what was the the mouth of the Tiber and a canal was dug to the Tiber. Construction work continued in the reign of Nero until AD 54. The city of Ostia, once the port of Rome and made much of in ancient sources as the place where Aeneas landed, was by this time almost 1 km inland because the Tiber had silted up. A second, hexagonal basin was added under Trajan. These measures were adopted primarily to secure grain supplies for Rome.