Domesday Book

The Domesday Book (or, colloquially, Domesday) is the expression used since the late twelfth century to refer to the record of the "Great Inquisition or Survey of the lands of England, their extent, value, ownership, and liabilities, made by order of William the Conqueror in 1086". Two volumes survive in The National Archives: "Great Domesday" covers parts of Wales and most of modern England except for northern areas then under control of the then Kingdom of Scotland and "Little Domesday" which covers in more detail Essex, Suffolk and Norfolk. The word Domesday is a Middle English spelling of doomsday, a day of judgment.

The survey was executed for William I of England (William the Conqueror): "While spending the Christmas of 1085 in Gloucester, William had deep speech with his counsellors and sent men all over England to each shire to find out what or how much each landholder had in land and livestock, and what it was worth" (Anglo-Saxon Chronicle).

Websites
Digital Versions of Domesday Book:
 * FamilySearch
 * National Archives, England
 * Open Domesday - First free online copy of Domesday Book