Archaeologists say they have uncovered what may be Britain's earliest known hospital.
Radio carbon testing at the site of a former leprosy hospital in Winchester, Hampshire, has revealed some burials took place between AD 960-1030.
Excavations revealed a range of buildings and "convincing evidence" for building foundations.
Until now, most historians believed hospitals in Britain only dated from after the Norman conquest of 1066.
A number of other artefacts and pits found at the site also relate to the same time, the archaeologists said.
Winchester was the capital of England throughout a large part of the Anglo-Saxon period and after the Norman Conquest, before London replaced it in the 12th Century.
Dr Simon Roffey, of the University of Winchester, which conducted the dig, said: "Historically, it has always been assumed that hospitals were a post-conquest phenomena, the majority founded from the late 11th Century onwards.
"However, our excavations have revealed a range of buildings and, more significantly, convincing evidence for a foundation in the 10th Century.
"Our excavations at St Mary Magdalen offer an intriguing insight into a little known aspect of the history of both Winchester and England. It is undoubtedly a site of national importance."
Prof Nicholas Orme, a leading researcher on medieval hospitals, added: "I have only studied the documentary evidence but I could not find any such evidence for a hospital before 1066 except perhaps as an activity within a monastery or minster.
"A late Anglo-Saxon hospital would surely be a first for archaeology and indeed for history."
One of the earliest known hospitals in Britain is Harbledown, in Canterbury, founded by Lanfranc in the 1070s, following the Norman Conquest.