Ostia Antica, Lazio

Ostia Antica is located at the mouth of the river Tiber, 25km to the west of Rome. A major port town in antiquity, Ostia now lies 3km from the coast of the Italian peninsula due to the deposition of sediment from the river. Since 2000, the BSR has conducted geophysical surveys at Ostia Antica as part of the Portus Project and on the behalf of other institutes.

In April 2000, a small geophysical survey was undertaken by the British School at Rome, on behalf of Dr. Janet Delaine of the University of Reading, behind the Insula of the Paintings at Ostia Antica. The aims and objectives of the survey were to test the application of resistivity as a means of locating sub-surface remains associated with the Insula as well as structures uncovered in an excavation outside the House of Jove and Ganymede. The survey was carried out with a Geoscan RM15 resistance meter in 2 areas of the site. The results successful located the line of a Roman drain and revealed a previously unknown series of rooms and corridors in both survey areas.

In November and December 2001, several geophysical surveys were undertaken by the University of Southampton and the BSR on behalf of the Deutsches Archäologisches Institut and The American Academy at Rome. The aim of the research was to apply geophysics to assess previously unexplored areas in the city, as well as those areas less well understood. The surveys were undertaken with a Geoscan Research Fluxgate Gradiometer over 11 areas at the site.

The survey located a series of structures north of the excavated city which would have followed the former course of the river Tiber during the Roman period. These formed a continuation of warehouses and insula blocks found in previous excavations. A strong linear feature which cuts along the discovered structures in this area has been interpreted as the line of a road along the river’s edge.

The results of the survey in the western area of the port suggested a continuation of the excavated structures sited along the course of the river. Many of the structures in this complex comprised horrea running in two lines from the river to the road, and mark the southern boundary of the port. The survey also located two new insula blocks and a portico in the vicinity of the theatre where previous reconstructions had envisaged only open space.

The 2001 season also identified the continued line of the defensive wall encompassing the south and west of the city with turrets being identified along the wall. Outside this wall, the presence of tabernae and a series of structures on the line of the roads leading out of the city were visible in the south east, while to the south west villa constructions with associated structures were found.

The final area investigated lay to the east of Ostia Antica, on the edge of the medieval borgo in an area known as Parco dei Ravennati. A gradiometry survey was undertaken immediately to the south-west of the Castello di Giulio II covering approximately 1 hectare. The results, whilst affected by modern disturbance, successfully recorded the line of a Roman road over approximately 100 metres. Further regular features were also recorded to the north and south of the road, probably marking the location of mausoleum and tombs.

In February and March 2005, magnetometry, resistivity and multiplexed-resistivity surveys were conducted by the University of Southampton and the BSR on behalf of the Soprintendenza in the garden of the Case degli Affreschi. The aim of this survey was to advance understanding of the 2nd century AD development of apartments in the south-west quadrant of the town, and to map the earlier Julian buildings buried beneath the garden areas of the Hadrianic era city. Other surveys were also carried out close to the present course of the River Tiber to investigate the existence of buried structures and the extent of a mosaic in the palestra of the Baths of the Forum.

The results in the Hadrianic gardens revealed colonnades associated with the garden plan of the 2nd century structures while features on a different alignment to the apartment blocks hinted at the existence of earlier building phases probably dating to the Julio-Claudian plan of the town.

The resistivity results from the area of the palestra close to the Baths of the Forum indicated the extensive remains of the mosaic that would have originally covered the entire area. The magnetometer survey conducted over the same area showed the appearance of earlier building structures that occupied the space later used for the palestra.