Welsh drought brings Roman and Iron Age aerial discoveries across the country

Figure 1. A tip-off from a Roman expert studying coin finds in central Wales led to this stunning discovery of a previously unrecorded Roman fort complex, showing as fading cropmarks in fields of wheat near Brecon, Powys (Crown Copyright RCAHMW, 1st August 2013).

The long spell of hot summer weather across Wales has left aerial archaeologists reflecting on some of their most significant discoveries since 2006. A previously unrecorded Roman fort, a Roman marching camp and scores of Iron Age farmsteads and forts have been discovered by the Royal Commission as parched grassland and ripening fields of wheat showed the locations of long-lost monuments. Aerial surveys over Cardiff and Pembroke Castles revealed parchmarks of lost buildings inside these well-visited attractions, while discoveries were made from Wrexham to Pwllheli, and from Haverfordwest to Chepstow.

Aerial archaeologist Dr Toby Driver from the Royal Commission carefully targeted reconnaissance flights in a light aircraft to where the drought conditions were most severe across the length and breadth of Wales. When cropmarks show in drought conditions, the Royal Commission’s aerial survey programme only has a few weeks to record the sites before rain or harvest removes them.

By far the most significant discoveries for Wales have been from the Roman period with a major Roman fort complex discovered near Brecon, and a Roman marching camp discovered near Caerwent Roman town. The Roman fort near Brecon is a rare discovery for Wales and was made following a tip-off from Roman scholar Dr Jeffrey L. Davies, who has worked with Toby on the Abermagwr Roman villa excavations. Toby explained:

‘Jeffrey Davies noticed an anomaly in Roman coin finds near Brecon, reported under the Portable Antiquities Scheme (PAS). He had a hunch that the coins, of the Emperor Claudius, could indicate a lost early Roman fort, and passed a grid reference to me the day before a flight into central Wales. I couldn’t believe my eyes when the pilot and I approached the location and saw fading cropmarks of a major Roman fort complex, lost beneath fields and a road for nearly 2,000 years.’

Other discoveries were made near Caerwent Roman town in south Wales, famously the market town of the Celtic Silures. Toby explained: ‘Close to Caerwent we discovered only the second Roman marching camp in Monmouthshire. These were overnight camps built by Roman soldiers on campaign in hostile territory. Because the campaigns against the tenacious Silures were documented by Roman historians, we expect more camps in south-east Wales than we currently know about. This new camp between Caerwent and Chepstow seems to show a small expeditionary force on manoeuvres, perhaps in the years around AD 50. West of Caerwent we found a remarkable ‘native’ Iron Age settlement. Given the decades of aerial survey in the region around Caerwent, these surprise discoveries show the continuing need for aerial archaeology in Wales.’

Figure 2. A rare discovery: only the second Roman marching camp in Monmouthshire, found between Caerwent and Chepstow, provides new evidence for the famous Roman campaigns against the Silures of south-east Wales. The characteristic ‘playing card’ shape of the camp shows as a cropmark in a ripening field of wheat, and an adjacent field of parched grass (Crown Copyright RCAHMW, 22nd July 2013).

Other discoveries made in the drought include one of the largest and most complex Iron Age defended farms in Pembrokeshire, on Conkland Hill, Wiston, as well as scores of newly recorded Iron Age farms and forts across south Pembrokeshire and in the Vale of Glamorgan, with two discovered close to the well-known Roman villa at Caermead, Llantwit Major. The archival work for the Royal Commission now begins, to catalogue and map the many discoveries and make the information more widely available to the public on its online database www.coflein.gov.uk


Learn more about aerial archaeology in Wales from the recent Royal Commission publication ‘Cymru Hanesyddol o'r Awyr / Historic Wales From the Air’ (RCAHMW 2012, £19.95) Dr Toby Driver, RCAHMW

How ‘cropmarks’  show lost archaeological sites

‘Cropmarks’ are revealed when grass and arable crops are put under drought stress, and they respond to subtle differences in moisture in the subsoil. Where crops are growing over the buried ditches of lost hillforts or prehistoric farms dark green lines form in fields; conversely buried stonework of lost buildings or old roads form yellow lines in grass and crops. These cropmarks can be seen most clearly from the air, but have to be photographed in a short time window before rain or harvest makes them disappear.
 

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