For centuries it has been widely believed that chaos quickly followed the end of Roman rule in Britain at the close of the fourth century.
But the discovery of the country's first known fifth century mosaic at a Roman villa reveals sophisticated life continued, at least in some places.
It had been thought that towns and villas were largely abandoned following the departure of the Romans, an economic crash and the beginning of the Dark Ages.
But radiocarbon dating has revealed that one of the mosaics at Chedworth in Gloucestershire was designed and created in the middle of the fifth century.