Domesday Book was commissioned by William the Conqueror (1066-1087) at Christmas 1085. It was designed to show who held every piece of land in the newly conquered Kingdom of England. It was known colloquially as the Domesday Book because it was seen as being as final as the Last Judgement and as difficult to conceal things from. The book does not cover the whole country - Cumberland, Durham, Northumberland, and Westmorland were omitted and London and Winchester likewise, along with some other towns. A separate book, called Little Domesday covered the counties of Essex, Norfolk and Suffolk and, despite its name, it is actually bigger and more detailed than the Great Domesday Book containing the other counties.

Oakley had two manors in 1086. The largest of these was owned by Robert de Tosny who had two men-at arms as tenants. These professional soldiers fought on horseback but were not considered noble and were not knights. They had four hides comprising seven villagers, three smallholders and five slaves and a mill worth twenty six shillings and two hundred eels. The value had been £4/10/- in 1066 when it was owned by a thegn called Oswulf. By the time de Tosny acquired it the value had fallen to £4 where it remained in 1086.

The second manor was owned by a niece of William I -  Countess Judith. She had been married to one of the few Anglo-Saxon nobles to survive William’s takeover, Earl Waltheof of Huntingdon and Northumbria. He rebelled twice against William and the second time paid for it with his head in 1076. Her holding was tenanted by a man named Miles Crispin and comprised half a hide. It had two smallholders meaning the population of Oakley was seven villagers, five smallholders and five slaves. This figure of seventeen is just the heads of household and should be multiplied by a factor of at least four, suggesting a total population of around seventy besides the two men-at-arms themselves and their households. Crispin’s manor had belonged to a man named Godwin in 1066 and had been worth twenty shillings. This value was halved by the time Judith acquired it and remained at that level in 1086.