Before the 1066 Norman conquest of England, the land and properties of Aldermaston formed part of the estates of Harold Godwinson, the Earl of Wessex, who later became King Harold II of England. Harold's assessment of Aldermaston valued the village's 15 hides at £20 a year. As with much of the land seized by William the Conqueror after his arrival in England in 1066, Aldermaston was held in demesne. His Domesday Survey of 1086 identified the existence of a mill, worth twenty shillings, and two fisheries, worth five shillings. During the rest of William's reign, and that of his son William Rufus, Aldermaston was owned by the Crown.