Two entranceways led up to gates to the northeast and southwest of the summit, where a timber fortress once stood.
The hill fort's flat summit was later extended to the west, possibly to accommodate a growing population.
"It's not a single build," Driver said. "New ramparts and new gateways were constructed over earlier ones."
Past archaeological finds, including a nearby cache of Bronze Age weapons, suggest the hill fort was active from about 900 B.C. until the Roman invasion of Britain in A.D. 43.
A bronze sculpture of a wild boar—a symbol of power—discovered in the 19th century in an adjacent field might be a relic of the ancient chiefs who ruled over Gaer Fawr, Driver suggested.
"It's a very rare find," he said. "One could conceive someone fairly powerful running the fort with this bronze boar mounted on his helmet."
The study team says the fort occupied a strategically important area for trade and agriculture between the fertile plains of England and the Welsh hills.
The border region has the highest concentration of Iron Age hill forts in Western Europe, Driver noted.
"This land would have supported a lot of people and hill forts would have risen up to control these populations," he said.
Phil Bennett is archaeological manager of one of the few extensively excavated Iron Age forts in Britain: Castell Henllys in southwestern Wales.
Larger hill forts such as Gaer Fawr commanded the surrounding landscape not just visually, but in terms of natural resources, Bennett said.
Huge amounts of timber would have been required both for building the fort palisades—strong defensive fences—and the dwellings people lived in, he said.
Roundhouses—circular buildings used as living quarters—excavated at Castell Henllys, for example, are estimated to have required some 30 oak trees, 80 to 100 hazel bushes, and 2,000 bundles of reeds, Bennett said.
(Related: "Badgers, Rabbits Undermine England's Ancient Monuments" [July 11, 2008].)
"We think these hill forts owed as much to elites showing off their status and power as any real need for defense," he added.
The terraced ramparts wouldn't have held an enemy at bay for long, according Bennett.
"Probably what was going on in the Iron Age was raiding rather than sieges and open warfare," Bennett said. "They would have taken things like cattle and people as slaves."
Another newly revealed feature at Gaer Fawr also hints at a much later period of occupation.
An angular bank dividing the interior of the fort is so different from the site's other earthworks that researchers suspect it dates to early medieval times.
"The fort has these prehistoric curving ramparts, but when you get to the top there's this big, straight bank which is very unprehistoric," the study team's Driver said.
After the Roman period, Welsh princes rose to prominence in the region, he added. "It may be that Gaer Fawr, in common with other hilltops in central Wales, was occupied by the court or castle of one of these early Welsh princes," Driver said.
Today, the once majestic site is a woodland recreation area.
"It's very difficult to imagine you're walking over an Iron Age hill fort," Driver said.
SOURCES AND RELATED WEB SITES