The name Warenne comes from the name of their property in Normandy where the family's ancestral castle, Bellencombre, was located on the Varenne River.
He also possessed the third penny (entitlement to one third of the fines levied in the county courts) of County Surrey and held the castles of Mortemer and Bellencombre in Normandy.
Following the acquisition of Normandy in April 1204, King Philip granted Renaud the county of Mortain and the honor of Warenne which was centered on the fortresses of Mortemer and Bellencombre.