WELSH historians believe they have uncovered the site of a 2,000-year-old city which they say is the most important location in ancient British history.

The Ancient British Historical Association (ABHA) claims that a field at Mynydd y Gaer near Pencoed is the fabled fortress city of King Caradoc I, or Caractacus, who fought the Romans between 42-51 AD.

The Roman leader at that time was the Emperor Claudius, immortalised by Derek Jacobi in the TV series and film I, Claudius, alongside Welsh actress Si n Phillips as his aunt Livia.

Historians Alan Wilson and Baram Blackett used old manuscripts to narrow their field of search and aerial photos obtained from Google Earth, which provides maps and satellite imagery, to find the exact spot.

Their findings have yet to be verified but the team are positive they have found the long lost site.

Mr Wilson said, "What we have is a clearly- defined walled city in exactly the place the records tell us it should be.

"The Welsh manuscripts and supporting records are always precise and allow us to make major progress in terms of identifying royal burial mounds, tombs, artefacts and more."

Tim Matthews, another member of the team, added, "We knew pretty much the area we were looking for and we knew that St Peter's Church nearby was an important meeting site and that it was at Caer Caradoc.

"So our area of search was limited to that area but because some land owners are less happy than others about people traipsing though their land access wasn't always easy.

"If you look at other ancient walled cities and what they may have been like you start to get an idea of the shape and the delineation and the patterning and you can see this is exactly what we're looking for."

Some experts have received the news with caution. A spokesperson at the Council for British Archaeology said, "Clearly it is very difficult to interpret early Welsh sources in relation to what is on the ground today.

"Although aerial photographs can be very revealing they can be very deceiving too. Without ground surveys and geophysical surveys to establish whether there were buried features, it would be difficult to say for certain whether it was an ancient site.

"That would be the next stage of investigation."

However the ABHA are sure of their findings.

Mr Matthews added, "With our research there's no theory and no speculation. You can read every manuscript, visit every site and touch every stone.

"You can go to places and see things - South Wales is littered with about 200 stones, dozens of grave mounds, tombs, all sorts of artefacts."

The group has gathered evidence from a number of ancient documents which they say refer to Caer Caradoc, including the Brut Tyssilio (684AD) and the later Gruffyd ap Arthur (1135AD).

Another reference is that of Teithfallt or Theodosius, who buried the 363 British noblemen murdered by treacherous Saxons at the notorious "Peace Conference" circa 456 AD at the Mynwent y Milwyr at Caer Caradoc.

According to the ABHA the Mynwent y Milwyr [monument to the soldiers] - is still to be found on the second highest point of Mynydd y Gaer above the possible site of the city of Caer Caradoc.

A third reference is that of the "Uthyr Pendragon", King Meurig or Maurice, who lies buried at the giant circle at Caer Caradoc.

There is, at this location, a gigantic ditch and mound shaped like a boat, next to St Peter's Church ruin not far from the site.

Mr Matthews believes that a historical discovery of this size could have important implications for the local economy.

"South Wales is packed with historical stuff and people just don't realise this.

"It's an area which is rich in ancient history you can actually touch.

"People love this kind of thing, they love it everywhere. People will come and see these things.

"It's regrettable that people in tourism agencies haven't done more."

When King Caradoc I, son of Arch, fought against the Romans between 42-51AD he was taking on a pretty big task.

At the time Rome was ruled by Emperor Claudius, or Tiberius Claudius Caesar Augustus Germanicus to give him his full name.

The first Roman Emperor to be born outside Italy, Claudius nonetheless oversaw the expansion of his empire, including the conquest of Britain.

His life was immortalised by English writer Robert Graves in his novels I, Claudius (1934) and Claudius the God (1935), which were adapted into the 1976 BBC TV series and film I, Claudius starring Derek Jacobi and Si n Phillips, pictured right.

However, as with many of the great Roman leaders, Claudius met his death at the hand of someone within his own household, poisoned either by his taster or his doctor. He died on October 13, 54AD.