Adelaide of Normandy (or Adeliza) (c. 1026 in Calvados, France[citation needed] - c. 1090) was the sister or half-sister of William the Conqueror.
She was the daughter of Robert the Magnificent, Duke of Normandy. Different chroniclers writing in the Gesta Normannorum Ducum call her sister of William the Conqueror by the same mother, or daughter of Robert by a different mother. She is usually said to be daughter of Herleva.[1]
Adelaide married three times; first Enguerrand II of Ponthieu (died 1053) by whom she had issue; second Lambert II, Count of Lens (died 1054); and third in 1060 Odo II of Champagne son of the Count of Troyes, (Odo IV of Troyes). By Lambert she had a daughter, Judith of Lens, who married Waltheof, Earl of Northumbria (executed 1076). Their daughter, Maud, 2nd Countess of Huntingdon, took for her second husband King David I of Scotland.
She gained the title of Princess when William the Conqueror became King of England[verification needed]. She became Countess of Aumale when her husband Odo inherited the title of Count in 1069.