CNN  — 

Archaeologists have uncovered Britain’s first 5th century Roman mosaic – a find of “enormous” historical significance which could change the way historians view the period it dates back to.

The mosaic floor was first discovered inside “room 28” at the Chedworth Roman Villa in Gloucestershire, England in 2017, but testing to verify the age of the floor has just been completed, UK conservation charity the National Trust said in a press release Thursday.

The date is significant because it had been believed towns and villas fell into decay after being abandoned following an economic crash in the 4th century.

Martin Papworth, National Trust archaeologist, said the 5th century marks the end of the Roman era in Britain and the beginning of the Dark Ages – when society is thought by some historians to have deteriorated in western Europe as a result of the Roman withdrawal.

An archaeologist at Chedworth Roman Villa exploring what lies underneath parts of the villa, some of which haven't ever been explored.

The Dark Ages, according to the National Trust, was also a period from which few documents survive, with archaeological evidence scarce.

National Trust researchers used radiocarbon dating – testing the level of carbon in charcoal and bone found in the area where the mosaic was found – and pottery analysis to pin down the “unexpected” age of the mosaic at the villa.

Chedworth Roman Villa is one of the largest Roman villas known in the country and one of the best preserved, according to the National Trust.

After the end of Roman rule in Britain, the army and civil service workers stopped being paid, which in turn triggered “production decline” among the craft and service industries, Papworth said in a statement.

The quality of the mosaic design possibly reflects this, as the National Trust said it was of “poorer quality” than those created in the 4th century.

Archeologists have discovered a mosaic that they say is of historical  significance.

However, its existence also indicates that society did not decline as rapidly as first thought, and that “sophisticated life” carried on for longer, particularly in southwestern England where the mosaic was found.

“It has generally been believed that most of the population turned to subsistence farming to sustain themselves and, after the break with Rome, Britannia’s administrative system broke down into a series of local fiefdoms,” Papworth added.

“What is so exciting about the dating of this mosaic at Chedworth is that it is evidence for a more gradual decline. The creation of a new room and the laying of a new floor suggests wealth, and a mosaic industry continuing 50 years later than had been expected.”

‘Tremendously exciting’

The mosaic was uncovered as part of a six-year program of archaeological research and digs at the Chedworth Roman Villa.

Papworth said: “It is interesting to speculate why Chedworth Villa’s owners were still living in this style well into the 5th century. It seems that in the West Country, the Romanised way of life was sustained for a while.

“Many large, richly decorated Roman Villas have been found in the countryside around Cirencester, which is around 8 miles from Chedworth.”

The mosaic indicates that the "Romanised" way of life continued in Britain long after the Romans had left the country.

Stephen Cosh, a Roman mosaic expert, said in a statement: “I am still reeling from the shock of this dating.”

“There are very late Roman mosaics in the area for which archeology can only ever say they must be later than a particular date, without being able to say how much later,” Cosh added.

“But none has ever been suspected to be this late. It will be important to research further sites in the region to see whether we can demonstrate a similar refurbishment at other villas which continued to be occupied in the 5th century. But there is no question that this find at Chedworth is of enormous significance – it’s tremendously exciting.”