===Dukes under the
Carolingians=== •
Nominoe (or
Nevenoe) ( 841–851), as a
missus dominicus of the
Emperor Louis the Pious, a count of
Vannes (Gwened) and arguably a duke (
dux) of Brittany •
Erispoe ( 851–857), as a duke, then as a king •
Salomon (or
Salaun) ( 857–874), as a duke, then a king •
Pasquitan (or
Paskweten) ( 874–877), ruling Brittany (southern part) with Gurvand •
Gurvand ( 874–877), ruling Brittany (northern part) with Pasquitan •
Judicael ( 877–888), successor of Gurvand, ruled Brittany (north) with Alan the Great (south) •
Alan the Great (reigned from 877 to 888 with Judicaël, alone as a duke, then as a king up to 907) •
Gourmaëlon, Count of
Cornouaille (reigned from 907 as a guardian of the kingdom) The succession was interrupted by the
Viking occupation (913–937)
House of Nantes ===House of
Rennes===
House of Cornouaille ===
House of Penthièvre=== ===
House of Plantagenet===
Eleanor, Fair Maid of Brittany, eldest daughter of Geoffrey and Constance and full elder sister of Arthur, also unmarried, was prevented from succession by her imprisonment in England which lasted till her death in 1241, thus was merely a titular duchess from 1208 to 1214 when
John, King of England ceased to support her claim.
House of Thouars ===
House of Dreux=== ===
Breton War of Succession=== ===
House of Montfort=== ===
House of Valois=== ==As courtesy title==