Enguerrand I, also Count of Montreuil (c. 1000 – c. 1045)
Hugh II, also Lord of Abbeville (c. 1045–1052) Father (by one account) of both Enguerrand II and Guy I.
Enguerrand II (1052–1053). Married Adelaide II daughter of Robert I Duke of Normandy. Succeeded by his brother (or by his son) Guy I:
Guy I, (1053–1100) Son (or brother) of Enguerrand II. Succeeded in Ponthieu by his daughter (and only surviving child):
Agnes (1100 – bef. 1105) b. c. 1080 in Ponthieu, France; d by 1105, possibly at the court of Adela, Countess of Blois to whom she had fled for refuge after imprisonment by her husband. Daughter of Count Guy I. Married c. 1087 (in the lifetime of the Conqueror) Robert of Bellême, 3rd Earl of Shrewsbury and Count of Alençon. Succeeded in Ponthieu by her only child:
William III Talvas (bef. 1105–?), also Count of Alençon. During his lifetime, he ceded Ponthieu to his elder son Guy II; Alençon went to his younger son John I (d February 24, 1191) who was married to Beatrice of Anjou, first cousin of Henry II of England, Count of Anjou.
Ponthieu was part of the Duchy of Normandy from 911 and played a small but important role in the politics that led up to the Norman invasion of England in 1066.
In 1067 the chaplain of Duchess Matilda, Gin de Ponthieu, Bishop of Amiens, composed a Latin poem on the battle of Hastings.