 Geographically detached parts of the manor (for example the tithings of Longham and North Ashley) may have resulted from the post-Civil War breakup of estates formerly belonging to the Lords Arundell of Wardour.The name probably derives from that of the Dorset Stour, which flows through the manor.At Christchurch, the Stour is joined by the Avon, and at one time the river upstream (west) of this point was known as the "West Stour", while downstream it was known as either the "East Stour" or "Stour & Avon".