Westmill was held by Aki, a thegn of Earl Harold, in 1066, and by Ansketil from Robert Gernon in 1086. It was assessed at 7 hides and 1 virgate, with 3 mills and woodland for 100 pigs as well as pasture for the livestock. The listed population of 18 villans, 5 Frenchmen, 12 bordars, 15 cottars and 2 slaves suggests a total population for the vill of more than 200 people.
Robert Gernon’s holdings were acquired by William de Montfitchet in the reign of Henry I. He was succeeded as overlord by Gilbert de Montfitchet (recorded before 1165-66), and then by Richard of the same family towards the end of Henry II’s reign. The Montfitchet overlordship came to an end on the death of another Richard, perhaps his son, in 1258. The tenancy was held by Ralph FitzHaselin and Richard Westmill in the time of William de Montfitchet, and later, during the reign of Henry II, by a family named Zoing. Hubert le Zoing held the tenancy in 1178 and his brother Jordan in 1183. They remained in possession well into the 13thc, as Geoffrey le Zoing was granted a market and fair at Westmill in 1226, and William le Zoing is mentioned in 1274.