Excavation and geophysical survey are uncovering the secrets of an exceptionally diverse Imperial Roman landscape.

The excavated finds (including marble and pottery) hold great potential for writing the economic and social history of the port, thereby making an important contribution to our understanding of its role in relation to Ostia, Rome and the Roman Mediterranean.

Portus, the great sea-port of Imperial Rome, is regarded as one of the most significant civil engineering works of the ancient world and yet, through a combination of historical circumstances, it has been the subject of surprisingly little archaeological research. The port area spans more than 2 km by 1 km and features a unique hexagonal harbour basin covering more than 32 hectares, itself equivalent in size to a middle-ranking Roman city. And stretching out from Portus lies an even larger area of archaeological interest – Isola Sacra – an artificial island created by Emperor Trajan on which is sited one of Italy’s best preserved Imperial Roman cemeteries.

For the past decade, a project aimed at answering many of the key questions surrounding this important site has been carried out by a collaboration between the Universities of Cambridge and Southampton, and the British School at Rome, in collaboration with the Soprintendenza per i Beni Archeologici di Ostia and the Duke Sforza Cesarini. The latest stage of the project began in 2007 with funding from the Arts and Humanities Research Council (AHRC), and combines a new survey using geophysical techniques with excavation of the core of the complex. Through this, the project aims to gain a fuller understanding of the historical and topographical development of this immense site, as well as to provide information that will help the Italian authorities manage it effectively.

Gateway to Rome

According to ancient texts, the construction of Portus was initiated by the Emperor Claudius, inaugurated by the Emperor Nero and enlarged by the Emperor Trajan. In the 1st century AD, Claudius ordered the construction of a great harbour and the digging of canals to drain the land at the mouth of the River Tiber. But it wasn’t until the early 2nd century, when Trajan constructed a hexagonal harbour basin and huge warehouses a little inland, that Portus became the main thoroughfare of imports from the Empire. Marble, glass, metalwork and foodstuffs arrived on ships from Egypt, Africa and the Mediterranean provinces bound for the Imperial city.

Under Trajan’s rule, the area due south of Portus in the Tiber delta was transformed into an artificial island defined to the east and south by the River Tiber, to the west by the Tyrrhenian Sea and to the north by a canal. A road traversed Isola Sacra, linking Portus with the adjacent city of Ostia, and along the road grew a major cemetery.

By the 6th century, however, the once bustling, cosmopolitan Portus had had its day, as Rome and her Mediterranean trade declined. Gradually, the mausolea, paintings, inscriptions, sculptures and mosaics of the necropolis were buried by sand dunes.

A hidden gem

Although records show that antiquarians and archaeologists have studied the ruins of Portus since the 16th century, and a substantial part of the Isola Sacra necropolis was excavated in the 1930s, the site has been effectively closed to study through most of the 20th century.

A major issue for the Italian antiquities agency has been how to manage and preserve this monumental landscape, which sits within an area of intensive modern development immediately adjacent to Rome’s main airport at Fiumicino. In the 1990s, they acquired much of the site to develop it as an archaeological park, opening up the area to new research such as the Portus Project.

Excavation and survey

The excavation led by Professor Simon Keay and Dr Graeme Earl from the University of Southampton is applying an integrated suite of techniques not widely used on complex Mediterranean sites, including digital recording and visualisation. A particular focus has been an area between the Claudian and Trajanic harbour basins that is helping to disentangle the structural sequence that runs from the 1st to the 6th century AD. It has already revealed unexpected details about the Claudian harbour, as well as information concerning the system for providing fresh water for ships to use at sea. The excavated finds (including marble and pottery) hold great potential for writing the economic and social history of the port, thereby making an important contribution to our understanding of its role in relation to Ostia, Rome and the Roman Mediterranean.

Professor Martin Millett from Cambridge’s Faculty of Classics and Kris Strutt from the University of Southampton are directing the geophysical component of the project. The new survey is attempting to cover all the areas of the Roman landscape on Isola Sacra that have not been built over. The first results from 2008 (covering about a third of the island) are already proving their worth. They show a sequence of relict pre-Roman coastlines left behind as the Tiber delta expanded westwards. Importantly, these join with those previously discovered in the survey of Portus to the north, demonstrating conclusively that no former east–west river channel existed in this area before the canals were dug in the 1st century.

Overlying this sequence of geological deposits are three different Roman landscapes. First, a settlement and buildings appear to be limited to the north margin of the island, along the course of the canal, and include marble wharves and a bridgehead settlement opposite Portus. Second, there is a series of land boundaries which imply that much of the island was given over to agricultural exploration, presumably to provide foodstuffs to the populations of Ostia and Portus. Finally, there are the funerary landscapes. These include both the dense concentration of tombs beside the road across the island as well as a smaller number of monuments overlooking the Tiber. The latter continue the pattern observed in the survey further north, and reflect the use of the Tiber as an artery for communication – the Roman dead were buried in tombs that were designed to be seen by travellers, whether travelling by road or by river.

Future fieldwork

Both the excavation and the survey are in their early stages and further discoveries are sure to follow over the next two seasons of fieldwork. However, it is already apparent that the integrated methodology being used – the geophysical survey to enhance understanding of the area’s layout together with the excavation of individual buildings and material culture – is yielding a breadth and depth of knowledge not previously available. In the process, this exceptionally rich and challenging site is also providing young academics and students from a range of countries with experience and training in site and survey techniques, electronic data capture and the identification and analysis of artefacts, fauna and botanical remains.

For more information, please contact the author Professor Martin Millett (mjm62@cam.ac.uk) at the Faculty of Classics or visit the Portus Project website (www.portusproject.org).

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