Research-2014

Potentia, Marche

2004-5

The Roman colony of Potentia lies south of the modern town of Porto Recanati, about 100m inland from the Adriatic coast on a beach ridge near the ancient mouth of the river Potenza. The geology of the area consists of a sandy beach ridge with local gravel beds lying under a thin layer of alluvial clay.

In two seasons, during September 2004 and September-October 2005, a geophysical survey was undertaken at the site by the Archaeological Prospection Services of Southampton (APSS) and the British School at Rome. The work was carried out on behalf of Prof. Frank Vermeulen of Ghent University, Flanders as part of the Potenza Valley Survey. The 2004 season represented a preliminary trial to test the capabilities of magnetometer survey with respect to this site by locating and mapping the remains of sub-surface archaeological features in the vicinity of the recent excavations at the monumental centre of the town.

Plate. 1. The republican temple complex excavated in the monumental centre of Potentia
The second season focused on an area in the south of the city to compare and contrast the results obtained by two other methods, air photography and field walking. Aerial photography conducted by Prof. Frank Vermeulen has revealed much of the road network associated with Potentia and both seasons of magnetometer survey aimed to clarify the layout of the Roman colony, the location of the circuit walls and the position of the west gate.

The results were very successful in revealing a comprehensive plan of almost half of the town that compliments both the aerial photography and the excavations at the site (See Figures 1 & 2 below). The nature of the features highlighted by the magnetometer survey was diverse, ranging from the large scale: identification of the public forum; to the very detailed: revealing successive rebuilding phases of the west gateway of the defensive walls.

The Roman colony of Potentia lies south of the modern town of Porto Recanati, about 100m inland from the Adriatic coast on a beach ridge near the ancient mouth of the river Potenza. The geology of the area consists of a sandy beach ridge with local gravel beds lying under a thin layer of alluvial clay.

In two seasons, during September 2004 and September-October 2005, a geophysical survey was undertaken at the site by the Archaeological Prospection Services of Southampton (APSS) and The British School at Rome. The work was carried out on behalf of Prof. Frank Vermeulen of Ghent University, Flanders as part of the Potenza Valley Survey. The 2004 season represented a preliminary trial to test the capabilities of magnetometer survey with respect to this site by locating and mapping the remains of sub-surface archaeological features in the vicinity of the recent excavations at the monumental centre of the town.

The second season focused on an area in the south of the city to compare and contrast the results obtained by two other methods, air photography and field walking. Aerial photography conducted by Prof. Frank Vermeulen has revealed much of the road network associated with Potentia and both seasons of magnetometer survey aimed to clarify the layout of the Roman colony, the location of the circuit walls and the position of the west gate.

The results were very successful in revealing a comprehensive plan of almost half of the town that compliments both the aerial photography and the excavations at the site (See Figures 1 & 2 below). The nature of the features highlighted by the magnetometer survey was diverse, ranging from the large scale: identification of the public forum; to the very detailed: revealing successive rebuilding phases of the west gateway of the defensive walls.

Fig.1. The magnetometer survey results after the 2004-5 campaigns.
Source: Vermeulen, F., Hay, S., Verhoeven, S. (2006) Potentia: an integrated survey of a Roman colony on the Adriatic coast. Papers of the British School at Rome 74: Fig.6, p214.

Fig. 2. Interpretation of the results shown in Figure 1.
Source: Vermeulen, F., Hay, S., Verhoeven, S. (2006) Potentia: an integrated survey of a Roman colony on the Adriatic coast. Papers of the British School at Rome 74: Fig.7, p215.

In the area extending along the extreme western perimeter of the field surveyed, traces of a stronger linear anomaly that runs north-northwest-south-southwest before turning sharply to the east can be seen. From comparison with air photographs it can be deduced that this feature probably represents the circuit of the city wall, which on the basis of two parallel negative anomalies, was flanked by ditches on either side. The survey also revealed that there may have been successive construction phases of the west gate which tally with the results of the excavation that exposed a period of rebuilding in the late 3rd and 4th century AD. Beyond the limits of the city wall the route of the cardo maximus can be traced uninterrupted heading west, lined by mausolea which appear as rectilinear and curvilinear anomalies in the results.

The results also clearly demonstrate the character of the town’s road network. A clear grid system aligned north-northwest-south-southeast is apparent. The principal decumanus maximus and cardo maximus can be traced and a sequence of other decumani and cardines was also detected, dividing the colony into a series of insulae. The nature of the buried remains does differ: in some cases distinct negative anomalies bordered by linear positive anomalies appear and in others just the edges are visible. This phenomenon is likely to be caused by variations in the road surface and compliments the findings from the excavation which observed that the decumanus maximus and cardo maximus were metalled while other roads were simply surfaced with battered river pebbles.

Dominating the results in the centre of the site is the discovery of the forum of Potentia. The open forum square, characterized by a dearth of structures, is clearly visible and is notable for its immense length and narrow width – approximately 30 x 120m. Flanking the western edge of the forum there is possible evidence for a series of shops fronted by a portico, mirroring the one visible in the excavations on the east side of the forum. To the north there is very clear evidence of a major structure bordering the forum square, whose layout, incorporating apses and small individual rooms arranged around a central courtyard, strongly suggests a bath-house complex or similar major public building. A further large structure, possibly a basilica, is also visible on the south edge of the forum.

Finally our survey has also succeeded in producing some evidence for urban housing. Fragments of buildings are visible all over the city, generally neatly aligned according to the street-grid. Several partial plans of houses, usually of types with central courtyards are also now discernible.

Considered together with the results of fieldwalking, aerial survey and targeted excavation the geophysical survey has greatly advanced our understanding of the colony of Potentia and firmly established it as one of best understood urban plans in Italy.

In the area extending along the extreme western perimeter of the field surveyed, traces of a stronger linear anomaly that runs north-northwest-south-southwest before turning sharply to the east can be seen. From comparison with air photographs it can be deduced that this feature probably represents the circuit of the city wall, which on the basis of two parallel negative anomalies, was flanked by ditches on either side. The survey also revealed that there may have been successive construction phases of the west gate which tally with the results of the excavation that exposed a period of rebuilding in the late 3rd and 4th century AD. Beyond the limits of the city wall the route of the cardo maximus can be traced uninterrupted heading west, lined by mausolea which appear as rectilinear and curvilinear anomalies in the results.

The results also clearly demonstrate the character of the town’s road network. A clear grid system aligned north-northwest-south-southeast is apparent. The principal decumanus maximus and cardo maximus can be traced and a sequence of other decumani and cardines was also detected, dividing the colony into a series of insulae. The nature of the buried remains does differ: in some cases distinct negative anomalies bordered by linear positive anomalies appear and in others just the edges are visible. This phenomenon is likely to be caused by variations in the road surface and compliments the findings from the excavation which observed that the decumanus maximus and cardo maximus were metalled while other roads were simply surfaced with battered river pebbles.

Dominating the results in the centre of the site is the discovery of the forum of Potentia. The open forum square, characterized by a dearth of structures, is clearly visible and is notable for its immense length and narrow width – approximately 30 x 120m. Flanking the western edge of the forum there is possible evidence for a series of shops fronted by a portico, mirroring the one visible in the excavations on the east side of the forum. To the north there is very clear evidence of a major structure bordering the forum square, whose layout, incorporating apses and small individual rooms arranged around a central courtyard, strongly suggests a bath-house complex or similar major public building. A further large structure, possibly a basilica, is also visible on the south edge of the forum.

Finally our survey has also succeeded in producing some evidence for urban housing. Fragments of buildings are visible all over the city, generally neatly aligned according to the street-grid. Several partial plans of houses, usually of types with central courtyards are also now discernible.

Considered together with the results of fieldwalking, aerial survey and targeted excavation the geophysical survey has greatly advanced our understanding of the colony of Potentia and firmly established it as one of best understood urban plans in Italy.

Reference

Vermeulen, F., Hay, S., Verhoeven, G. (2006) Potentia: an integrated survey of a Roman colony on the Adriatic coast. Papers of the British School at Rome 74: 203-36.

Image Reference

Plate 1. Vermeulen, F. (2003) The Potenza Valley Survey: Preliminary Report on the Field Campaign 2003. Universiteit Gent.