Portus - The harbour of Trajan

Trajan added a second, internal basin behind the basin that had been dug by Claudius. It was hexagonal in shape, for harbours a unique shape. It has been suggested that it was designed by Apollodorus of Damascus, the architect of Trajan's forum in Rome. The work was carried out in the years 100-112 AD. The sides of the hexagonal basin measured 357.77 meters. The maximum diameter was 715.54 meters. It was seven meters deep. The bottom was covered with stones, at the north end gradually sloping upwards, to reach a depth of only one meter at the edge of the basin. In the quays were travertine blocks with holes, used for mooring, fifteen metres apart. Many new warehouses were built around the new basin, so that the total storage capacity was now much greater.

A mooring block. Testaguzza 1970, p. 104.

The basin was surrounded by a few wide treads, leading to quays that were only a few meters wide. Columns with Latin numerals were found around the basin, so apparently the sides of the hexagon were subdivided into numbered sectors. On the quays was a wall, with five narrow doorways on each side of the hexagon. The doorways are too narrow for wagons (1.80 m.). Apparently the goods were unloaded and carried by porters. This can also be seen on several reliefs and mosaics. The wall facilitated the control of the flow of goods, for the customs service and the levying of import duties (the portorium). The basin could contain more than 100 ships, that did not moor alongside the quays, but at a straight angle.

A Trajanic coin of the hexagonal basin.

This second harbour was called Portus Traiani or Portus Traiani Felicis, "the port of the happy Trajan". The ports of Claudius and Trajan together were called Portus Uterque ("Both Ports"), but also Portus Augusti et Traiani Felicis.

A bridge named after Matidia, a niece of Trajan, spanned the Fossa Traiana, thus connecting Portus and the Isola Sacra. Fire-fighters (vigiles) were stationed in barracks. Several temples were built (significantly often with Greek dedications), including a temple of Liber Pater on a square used for auctions of wine. In front of this Forum Vinarium stood a colossal statue of an armoured Trajan, facing the entrance of the hexagonal basin. Houses and apartments have not yet been found in Portus. Initially many people working in Portus may have lived in Ostia, but in the later second century the famous physician Galenus wrote that both Ostia and Portus were populous centres. The habitations were then probably for the most part located to the south of the hexagon.

Trajan's basin. Photo: Jan Theo Bakker.

Initially the administration of Ostia, so the city council (ordo decurionum) and magistrates led by mayors (duoviri), controlled Portus. The Imperial representative in the harbours was a procurator Portus. In Ostia the Imperial government was represented by a procurator Annonae, working for the praefectus Annonae in Rome. Trajan however seems to have withdrawn Portus from the jurisdiction of Ostia. The two harbour basins and the surrounding commercial buildings and infrastructure were from now on owned by the city of Rome. Ostia was the place where contracts and finances were discussed. Portus on the other hand was the place where the practicalities of the seaborne imports were handled, now overseen by a procurator Portus Utriusque, of "both harbours" (that of Claudius and that of Trajan, not Ostia and Portus).