Count of Ponthieu
The County of Ponthieu (, ), centered on the mouth of the Somme,  became a member of the Norman group of vassal states when Count Guy submitted to William of Normandy  after the battle of Mortemer. It eventually formed part of the dowry of Eleanor of Castile and passed to the English crown. Much fought-over in the Hundred Years' War, it eventually passed to the French royal domain, and the title Count of Ponthieu (comte de Ponthieu) became a courtesy title for the royal family. Counts and Countesses of Ponthieu
Helgaud III, also Count of Montreuil. d. 926 in combat against the Normans. Herluin II or Herlouin, also Count of Montreuil. (926–945)
Roger or Rotgaire or Notgard, also Count of Montreuil. (dates unknown)
William I, also Count of Montreuil. (dates unknown)
Hildouin, also Count of Montreuil. (dates unknown)
Hugh I, also Count of Montreuil, d. c. 1000. 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) brother (or son) 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 1103 Married c. 1087 Robert of Bellême, 3rd Earl of Shrewsbury and Count of Alençon. Succeeded in Ponthieu by her only child:
William III Talvas (bef. 1105–20 June 1172), 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. Guy II (?–1147). Succeeded by his elder son:
John I (1147–1191) Succeeded by his son:
William IV Talvas (1191–1221), also Count of Montreuil. Succeeded by his daughter:
Mary (1221–1251), also Countess of Montreuil. married Simon of Dammartin (1213 1239) Succeeded by their daughter:
Joan (1251–1279), also Countess of Montreuil. married Ferdinand III of Castile (1198/1199–1252)
Eleanor (1279–1290), also Countess of Montreuil. Edward II of England (1290–1325), also Count of Montreuil. Edward III of England (1325–1336), also Count of Montreuil. confiscated by Philip VI of France
James I, Count of La Marche (1351–1360)
returned by the Peace of Brétigny
Edward III of England (1360–1369)
confiscated again
Charles VII of France (1403–1422)
royal domain
Charles de Valois, Duke of Angoulême (1573–1650)
Louis Emmanuel de Valois, Duke of Angoulême (1650–1653)
royal domain
Charles de Bourbon, Duc de Berry (1710–1714)
royal domain
Charles X of France (1830–1836)

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