In or before 1063 [his father] Hoël Canhiart II Duke Brittany (age 32) and [his mother] Hawise Penthièvre Countess Cornouaille were married. She by marriage Countess Cornouaille. He by marriage II Duke Brittany. The date based on the birth of their first child Alan Canhiart IV Duke Brittany in 1063. She the daughter of [his grandfather] Alan Penthièvre III Duke Brittany and [his grandmother] Bertha Blois Duchess Brittany (age 57). He the son of [his grandfather] Alan Canhiart Count Cornouaille and [his grandmother] Judith Poher Countess Cornouaille and Nantes.

In 1080 Stephen Blois II Count Blois and Chartres (age 35) and [his future sister-in-law] Adela Normandy Countess Blois (age 13) were married at Chartres [Map]. She by marriage Countess Blois. The difference in their ages was 22 years. She the daughter of [his future father-in-law] King William "Conqueror" I of England (age 52) and Matilda Flanders Queen Consort England (age 49). He the son of Theobald Blois III Count Blois (age 68) and Gersenda Maine Countess Blois. They were third cousins.

In 1087 Alan Canhiart IV Duke Brittany (age 24) and Constance Normandy Duchess Brittany (age 30) were married. She by marriage Duchess Brittany. She the daughter of King William "Conqueror" I of England (age 59) and Matilda Flanders Queen Consort England. They were third cousins.

In 1088 William "Troubadour" Poitiers IX Duke Aquitaine (age 16) and [his future wife] Ermengarde Anjou Duchess Brittany and Aquitaine (age 20) were married. She by marriage Duchess Aquitaine. She the daughter of [his future father-in-law] Fulk "Réchin" Anjou 4th Count Anjou (age 45) and Hildegarde Beaugency Countess Anjou (age 44). He the son of Guy William Poitiers VIII Duke Aquitaine and Hildegarde Burgundy Duchess Aquitaine (age 32). They were half first cousins.

In 1093 Alan Canhiart IV Duke Brittany (age 30) and Ermengarde Anjou Duchess Brittany and Aquitaine (age 25) were married. She by marriage Duchess Brittany. She the daughter of Fulk "Réchin" Anjou 4th Count Anjou (age 50) and Hildegarde Beaugency Countess Anjou (age 49). They were third cousin once removed.

Before 25 Oct 1102 [his former brother-in-law] Robert Curthose III Duke Normandy (age 51) and Sybilla Conversano Duchess Normandy were married. She by marriage Duchess Normandy. He the son of [his former father-in-law] King William "Conqueror" I of England and Matilda Flanders Queen Consort England.

In 1110 [his brother-in-law] Fulk "Young" King Jerusalem (age 21) and Ermengarde La Flèche De Baugency Countess Anjou were married. She by marriage Countess Anjou. She the daughter of Elias La Flèche De Baugency I Count Maine and Matilda Chateau Du Loir Countess Maine. He the son of [his father-in-law] Fulk "Réchin" Anjou 4th Count Anjou and Bertrade Montfort Queen Consort France (age 40).

Before 1113 [his son] Conan "Fat" Canhiart III Duke Brittany (age 17) and [his daughter-in-law] Matilda Fitzroy Duchess Brittany were married. She by marriage Duchess Brittany. She the illegitmate daughter of [his former brother-in-law] King Henry I "Beauclerc" England (age 44). He the son of Alan Canhiart IV Duke Brittany (age 49) and [his wife] Ermengarde Anjou Duchess Brittany and Aquitaine (age 44). They were fourth cousins.