The
Counts of Nantes were originally the
Frankish rulers of the
Nantais under the
Carolingians and eventually a capital city of the
Duchy of Brittany. Their county served as a
march against the
Bretons of the
Vannetais. Carologinian rulers would sometimes attack Brittany through the region of the
Vannetais, making Nantes a strategic asset. In the mid-ninth century, the county finally fell to the Bretons and the title became a subsidiary title of the Breton rulers. The control of the title by the Breton Dukes figured prominently in the history of the Duchy. The title Count of Nantes was given to Hoel, a disinherited son of a Duke. He lost the Countship due to a popular uprising. That uprising presented an opportunity for King
Henry II of England to attack the Breton Duke. In the treaty ending their conflicts, the Breton Duke awarded the Countship of Nantes to Henry II.