The harbour of Trajan
The wide and shallow expanse of water in Claudius' basin may have been vulnerable, witness the events of 62 AD. This may have been one of the reasons why Trajan built a second, hexagonal basin behind the basin of Claudius. The work was carried out in the years 100-112 AD, and included improvements of the Claudian harbour. The capacity of the harbour was much greater now, and many new warehouses were built around it. The sides of the hexagonal basin measure 357.77 metres, perhaps 1200 Roman feet. The maximum diameter is 715.54 metres. It was five metres deep. On the quays were travertine blocks with holes, used for mooring, fifteen metres apart (h. 1.10, w. 0.75, d. 2.0, diam. of holes 0.45). The basin could contain more than 100 ships that did not moor alongside the quays, but at a straight angle. Numbered columns with Latin numerals were also found around the basin, suggesting that the sides of the hexagon were subdivided into numbered sectors. On the quays was a wall with five narrow doorways (1.80) on each side of the hexagon. Apparently the goods were unloaded by slaves only, who did not use wagons. This can also be seen on several reliefs and mosaics. The wall facilitated the control of the flow of goods, for the Customs Service.
The hexagon may have been designed by Apollodorus of Damascus, the architect of Trajan's Market in Rome. No other harbours are known with this shape, suggesting that it was chosen not only for practical purposes, but also for aesthetic reasons, emphasizing the power of Rome and the Emperor.
A Trajanic coin of the hexagonal basin.
A badly preserved inscription from the years 102-109 AD (Thylander B312) mentions a channel and inundations of the Tiber:
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[imp caes divi] NE[rvae f nerva] TRA[ianus aug germ] DAC[icus trib pot] I[mp cos pp] FOSSAM [fecit] [q]VA INVN[dationes Tiberis] [ad]SIDVE V[rbem vexantes] [rivo p]EREN[ni instituto arcerentur] |
This curved channel, c. 35 metres wide, connected the Tiber and the Claudian "Fossa Traiana". It was flanked by towpaths. Other channels connected the basin with the basin of Claudius and the Fossa Traiani. The plan of Labacco shows two bridges over the latter channel, but whether these really existed is quite uncertain.
This harbour was called Portus Traiani or Portus Traiani Felicis. The two harbours together were called Portus Augusti et Traiani Felicis, but also Portus Uterque ("Both Harbours"). The urban settlement, a district of Ostia, was known as Portus.
Trajan's basin in the dusk of evening.
Photograph: Jan Theo Bakker.
[jthb - 30-Mar-2008]