Hawise, Duchess of Brittany

Hawise of Rennes ( b.c. 1037 - August 19 1072 ) was hereditary Duchess of Brittany from 1066 until her death in 1072. She was the second child and heiress of Conan I, Duke of Brittany by his wife Berthe de Blois, and member of the House of Rennes. Hawise survived her older brother Conan II, Duke of Brittany, who died of assination by poisioning on December 11, 1066.

Little is known of the life of Hawise of Rennes (Breton: Hawiz Roazhon). As with most noble women in the middle ages hers may have been a political marriage with Hoel of Cornwall (French Cornouaille, Breton Kerne). A dynastic alliance between the house of Rennes in the east and the house of Cornwall in the west may have further strenghtened Brittany. Hoel may have excercised authority through the right of his wife, and continued to control the government after her death in 1072. Hawise and Howel were succeeded to the ducal throne by their 18-year-son son Alan IV, Duke of Brittany in 1084.

Brittany, an independent Celtic duchy, had a traditional rivalry with neighboring Normandy. The 1064 -1065 War between Brittany and Normandy was sparked after Duke William suported Rivallon I of Dol's rebellion against Conan II. By late 1065, preparing for his invasion of England, Duke William sent a communiqe to Conan II warning his neighbors not to attack Normandy while he invaded England, which Duke Conan II rebuffed . A year latter, Conan II was killed after donning poisoned riding gloves in a campaign against Anjou. Duke William of Normandy was widely suspected of having Conan II assinated.