Friday, September 07, 2012

Roman provicial town revealed – street by street

An ancient Italian town, which disappeared 1,500 years ago after it was finally abandoned by it's inhabitants now lies buried beneath the ground. The site has been mapped by archaeologists using the latest remote sensing technology, revealing the location of its theatre, marketplace and other buildings.

A lost town

Originally founded as a colony in the 4th century BCE, the site of Interamna Lirenas lies in the Liri Valley in Southern Lazio, about 50 miles south of Rome itself. It was founded in 312 BCE as a colony of Latins in an area already settled by Volscans , on the route of the Via Latina. It was situated at the confluence of the Liri and Rio Spalla Bassa rivers, where the name "Interamna" (meaning "between river"). It was abandoned around the year 500 CE, and then scavenged for building materials until today, the site is an uninterrupted stretch of farmland, with almost no recognisable archaeological features.

Geophysical archaeologists have now successfully produced the first images of the ancient site, using methods that allowed them to survey beneath the surface of the earth and map the layout of the entire settlement, which spans 25 hectares.

Archaeologists using magnetometry equipment at the site of Interamna Lirenas. Credit: University of Cambridge.

The resulting pictures have already thrown up a few surprises. Scholars had previously imagined that the Roman town of Interamna Lirenas was something of a sleepy backwater, but the large marketplace and theatre instead suggest that, in fact, it was a bustling economic and social centre.

Martin Millett, Laurence Professor of Classical Archaeology at the University of Cambridge and Fellow of Fitzwilliam College, said, "Having the complete street-plan and being able to pick out individual details allows us to start zoning the settlement and examine how it worked and changed through time."

The completed images are the result of a project which began in 2010 that aims to understand more about what happened in towns established by the Romans as colonies in Italy following her conquest.

A glimpse at early town plans

Interamna Lirenas is an enticing case study because, in spite of its size, it did not expand significantly during the high point of Rome's Imperial age, meaning that it retained much of its original colonial shape and features.

It became a municipium in 90 BCE, assimilated fully into the governmental systems of Rome.

Thanks to antiquarian research, archaeologists have long since known that a town existed on the site, but it has never been excavated. One reason is that until relatively recently, experts believed that all Roman colonial settlements followed the same template – something which the new pictures from Interamna Lirenas are now helping to question.

Knowing that a full-scale excavation of such a large area would be impractical, the research team decided to carry out a systematic geophysical analysis instead.

The main techniques they used were magnetometry and Ground Penetrating Radar (GPR). Magnetometry measures minute variations in the earth's magnetic field caused by different features beneath the surface, and this allowed the researchers to identify the town's overall layout, many individual buildings and a wide open area in the settlement's centre – its forumor marketplace.

1) Magnetometry image of theatre with GPR overlay (2). The GPR enabled researchers to pick out the shape of the seating in finer detail and allow the theatre shape (3) to be overlaid. Credit: University of Cambridge.