With its Iron Age hill fort, medieval abbey ruins and 19th-century castle, Margam Country Park in Wales offers plenty of history for its regular stream of visitors.
But the most spectacular relic of all appears to lie around three feet below ground.
Archaeologists announced on Monday that they had detected the outline of the largest stand-alone Roman villa structure to be uncovered in Wales.
It appears to be particularly well preserved because it lies beneath a deer park that was never disturbed by cultivation or construction.
The discovery was made using geophysical surveys, which use high-resolution magnetometry and ground radar data to detect objects below the surface. Although excavation has yet to begin, Alexander Langlands, an associate professor at Swansea University who is leading the project, describes the discovery as the “Pompeii of Port Talbot” — referring to one of the world’s most famous archaeological sites and to a nearby Welsh town that is famous for its steelworks.
“It was like being a 12-year-old all over again,” he said, recalling his first sight of the images. “I was really, really excited.”
More structures are likely to be buried nearby, Dr. Langlands said in a phone interview, including a possible Roman bathhouse.
The surveys show that the villa occupied an enclosure spanning roughly 43 meters by 55 meters, or 141 feet by 180 feet. Its fortified structure suggests that it was equipped for defense against aggressors from the east and west. That was often necessary in the unstable years toward the end of the Roman occupation of Britain, which began in A.D. 43 and lasted until the fifth century.
During this time, the Romans conquered most of Wales despite resistance from Indigenous tribes. Most Roman remains that have been excavated in Wales are from military fortifications or marching camps.
That makes the discovery of a villa — of a size and scale that would not seem out of place in the center of Roman England — particularly significant, Dr. Langlands said. It could show that Wales was not a “kind of liminal borderland” region, he added, but “just as Roman as anywhere else we’ve got in the heartlands of the province of Britannia.”
The geophysical surveys revealed a substantial aisled building southeast of the main villa. This is believed to have been either a large agricultural storage facility or a structure dating from the later history of the site, possibly a meeting hall for post-Roman leaders and their followers.
