Adelaide of Normandy (c. 1026 in Calvados

Calvados

The French department of Calvados is part of the region of Basse-Normandie in Normandy. It takes its name from a cluster of rocks off the English Channel coast...

, France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

- 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

Gesta Normannorum Ducum

Gesta Normannorum Ducum is a chronicle originally created by the monk William of Jumièges just before 1060. In 1070 William I had William of Jumièges extend the work to detail his rights to the throne of England. In later times, Orderic Vitalis and Robert of Torigni Gesta Normannorum Ducum (Deeds...

call her sister of William the Conqueror either by the same mother or by different mothers. She is usually said to be daughter of Herleva

Herleva

Herleva also known as Herleve, Arlette, Arletta and Arlotte, was the mother of William I of England. She had two other sons, Odo of Bayeux and Robert, Count of Mortain, who became prominent in William's realm....

.

Adelaide married three times; first Enguerrand II of Ponthieu

Enguerrand II, Count of Ponthieu

Enguerrand II was the son of Hugh II count of Ponthieu. He assumed the county upon the death of his father on November 20, 1052.The Ponthievin alliance with duke William of Normandy had earlier been secured by the marriage of Enguerrand's sister, to duke William's uncle, William of Talou....

 (died 1053) by whom she had issue; second Lambert II, Count of Lens

Lambert II, Count of Lens

Lambert II, Count of Lens was a French nobleman.He was the son of Eustace I, Count of Bologne and of Maud de Leuven . He married Adelaide of Normandy, Countess of Aumale, daughter of Robert I, Duke of Normandy. Lambert was killed at the Battle of Lille. He had a daughter, Judith of Lens and two...

 (died 1054); and third in 1060 Odo II of Champagne son of the Count of Troyes, (Odo IV of Troyes), by whom she had issue Stephen, Count of Aumale

Stephen of Aumale

Stephen of Aumale was Count of Aumale from 1082 to 1127.He was son of Eudes de Blois, Count of Troyes and Count of Meaux, and Adelaide of Normandy, countess of Aumale, and sister of William the Conqueror...

. By Lambert she had a daughter, Judith of Lens

Judith of Lens

Countess Judith , was a niece of William the Conqueror. She was a daughter of his sister Adelaide of Normandy, Countess of Aumale and Lambert II, Count of Lens....

, who married Waltheof, Earl of Northumbria (executed 1076). Their daughter, Maud, 2nd Countess of Huntingdon

Maud, 2nd Countess of Huntingdon

Maud of Northumbria , Countess of the Honour of Huntingdon and Northampton, was the daughter of Waltheof II, Earl of Northumbria and Judith of Lens, the last of the major Anglo-Saxon earls to remain powerful after the Norman conquest of England in 1066.- Biography :Maud was married to Simon of...

, took for her second husband King David I of Scotland

David I of Scotland

David I or Dabíd mac Maíl Choluim was a 12th-century ruler who was Prince of the Cumbrians and later King of the Scots...

.

She became Countess of Aumale when her husband Odo inherited the title of Count in 1069.