The County of Mortain was a medieval county in France centered on the town of Mortain. A choice landholding, usually either kept within the family of the duke of Normandy (or the king of France) or granted to a noble in return for service and favor. This was the main reason Mortain had so many counts, as shown below, during its long history.
County established by Charlemagne 786
Unknown
Rodulf of Tosny (812–861)
Hugh of Nogent (861–911)
Vacant after Rollo's invasion
Adémar of Boulogne (918–977)
Mauger of Corbeil (977–1032)
William Werlenc(1032–1048)
Robert, Count of Mortain (See also: Robert of Conteville) 1049–1104)
William, Count of Mortain (1104–1106)
Robert II of Vitry (1106–1112)
Stephen of England (1112–1135)
Eustace IV of Boulogne (1135–1141)
Geoffrey of Anjou (1141–1144)
William of Blois (1154–1159)
Vacant
Marie of Boulogne and Matthew of Alsace (1167–1173)
Vacant
John I of England (1189–1199) (lost to France)
Ida, Countess of Boulogne and Renaud de Dammartin (1204–1216)
Matilda II of Boulogne (1216–1245) and...
Philip Hurepel (1216–1233)
Afonso III of Portugal (1238–1245)
Jeanne de Dammartin (1245–1251) and ..
Walter of Châtillon (1245–1250)
Vacant
Joan II of Navarre (1328–1349)
Vacant
Peter d'Évreux (1401–1412)
Catherine of Alençon (1412–1416) (his widow) and..
Louis, Duke of Guyenne (1412–1413)
Louis VII of Bavaria, Duke of Bavaria-Ingolstadt (1413–1416)
Jean Dunois (1416–1417) and..
Charles of Le Maine (1416–1417)
Charles of Valois, Duke of Berry (1416–1417)
Edward (1417–1419)
Thomas Langholme (1419–?)
John of Lancaster, 1st Duke of Bedford (?–1435)
Edmund Beaufort, 2nd Duke of Somerset (1435–1449)
Charles of Le Maine (1449–1472)
Charles IV, Duke of Anjou (1472–1481)
Royal Domain
Louis II, Duke of Montpensier (1529–1582)
Francis, Duke of Montpensier (1582–1592)
Henri de Bourbon, duc de Montpensier (1592–1608)
Marie de Bourbon, duchesse de Montpensier (1608–1627) and..
Gaston de France, duc d'Orléans (1626–1660) (her widower)
Anne Marie Louise d'Orléans, duchesse de Montpensier (1660–1693)
Philippe de France, duc d'Orléans (1693–1701)
Philippe II d'Orléans, duc d'Orléans (1701–1723)
Louis d'Orléáns, duc d'Orléans (1723–1752)
Louis Philippe I d'Orléans, duc d'Orléans (1752–1785)
Louis Philippe II d'Orléans, duc d'Orléans (1785–1786)
Royal Domain
Henri d'Orléans, comte de Paris, duc de France (1984–present)
List of counts of Mortain Wikipedia (Text) CC BY-SA