Norman cavalry charging on the Saxon shield wall, from the Bayeux Tapestry
When William the Conqueror wanted to consolidate his power over his new English subjects he created the Domesday Book.
It was a comprehensive list of who owned all property and livestock.
Now Cambridge University historians have digitised the information in an interactive website.
"It's possible for anyone to do in a few seconds what it has taken scholars weeks to achieve," said Dr Stephen Baxter, a co-director of the project.
was launched on 10 August 2010 and is the result of collaboration between scholars from Cambridge University and King's College, London.
The Domesday Book was collated between 1085 and 1086.
Most historians believe it is some sort of tax book for raising revenue.
Dr Baxter, a medieval historian from King's College, London, has a different theory.
He argues its real purpose was to confer revolutionary new powers on King William.
"The inquest generated some pretty useful tax schedules," he explained. "But the book gave him something altogether more powerful."
In just 20 years the Norman barons had been involved in an extensive land grab from the Saxon nobility. William now had exact data on who owned what and where, and he could demand loyalty with the threat of dispossession.
"Having a tool of political control of the landed elite gave him something far more important in the end than taxation," Dr Baxter believes.
This theory is explored in
a BBC Two programme on 10 August 2010, presented by Dr Baxter.
Stephen Baxter is a Cambridgeshire man. He grew up in Bourn, and was educated at Comberton Village College and Hills Road Sixth Form College.
Cambridge's Market Square, castle and Round Church all feature in the Domesday programme.
He also visited Bourn, where his parents still live, to give an example of the impact of the Norman conquest on a typical English village.
Access for all
Edward the Confessor with Harold Godwinson, from the Bayeux Tapestry
The PASE Domesday website includes masses of data from the Saxon era, as well as material gathered for the Domesday Book.
It is not just for scholars.
Anyone can key in the details of where they live to find out who the landowner would have been in 1066, the year of the Norman Conquest, and who it was by 1086.
By then, the transfer of power and property from the Anglo-Saxon aristocracy to the Normans was extensive.
Visitors can also create maps and tables of the estates held by the same lords elsewhere in England, and examine the scale of this dispossession.
The website forms part of a wider project, The Prosopography of Anglo-Saxon England (PASE), which aims to capture information relating to all the recorded inhabitants of England, from the late sixth to the late 11th century, in a single online database.
It will be launched later in 2010.
PASE Domesday is designed to help answer one of the great unsolved questions of English medieval history, 'What was the structure of English landed society in 1066?'
To create the website, researchers painstakingly processed the vast quantity of data found in the various products of the Domesday survey of 1086.
"The breakthrough has been made possible by the wonders of modern technology, in selecting and arranging the data, in generating the maps, and in presenting the possibilities," said Professor Simon Keynes, of the Department of Anglo-Saxon, Norse and Celtic at Cambridge University, and a co-director of the PASE project.
"One can then begin to detect the patterns and to make the informed judgements which will help to produce a significant result."
PASE Domesday promises to change people's understanding of English society on the eve and in the aftermath of the Norman Conquest.