Jean IV de Montfort, duc de Bretagne

Is your surname de Montfort?

Research the de Montfort family

Jean IV de Montfort, duc de Bretagne's Geni Profile

Share your family tree and photos with the people you know and love

  • Build your family tree online
  • Share photos and videos
  • Smart Matching™ technology
  • Free!


Jean IV of de Montfort (de Dreux)

Also Known As: "John", "Duke of Brittany"
Birthplace: Hennebont, Brittany, France
Death: Died in Hennebont, Morbihan, Bretagne, France
Place of Burial: Sainte-Croix, Quimperlé, Finistère, Bretagne, France
Immediate Family:

Son of Arthur II de Dreux, duc de Bretagne and Yolande de de Dreux, Countess of Montfort, Queen consort of Scots
Husband of Alice de la PLAUNCHE and Jeanne of de Nevers
Father of Jean V de Montfort, duc de Bretagne and Jeanne de Bretagne
Brother of Béatrix de Dreux; Alix de Bretagne; Jeanne de Bretagne; Marie de Monfort and Blanche de Monfort
Half brother of Jean III de Dreux, duc de Bretagne; Guy VII de Limoges, comte de Penthièvre and Pierre de Dreux, seigneur d'Avesnes

Occupation: Duc de Bretagne
Managed by: Private User
Last Updated:

About Jean IV de Montfort, duc de Bretagne

John IV of Montfort (in Breton Yann Moñforzh, in French Jean de Montfort) (1295 – 16 September 1345 Château d'Hennebon), was duke of Brittany, from 1341 to his death. He was son of Duke Arthur II and Yolande de Dreux, countess of Montfort, his second wife.

Marriage and issue

In 1322 he succeeded his mother as count of Montfort, and in 1329, he married Joanna of Flanders at Chartres. They had two children:

John V, Duke of Brittany (1339–1399)
Joan of Brittany, Baroness of Drayton (1341 – aft. 20 October 1399), married before 21 October 1385 Ralph Basset, 4th Baron Basset de Drayton

Breton War of Succession

When his half-brother, duke John III, died with no male heirs in 1341, John IV decided to contest the rights of his niece, Joanna of Penthièvre, and her husband, Charles of Blois, to the duchy of Brittany. This led to the Breton War of Succession part of the Hundred Years' War. His patron in this quest was king Edward III of England.


view all

Jean IV de Montfort, duc de Bretagne's Timeline

Hennebont, Brittany, France
Age 36
Chartres, Eure-et-Loir, Maine, France
November 1339
Age 46
Nantes, Loire Atlantique, Pays de la Loire, France
Age 48
September 26, 1345
Age 52
Hennebont, Morbihan, Bretagne, France
Sainte-Croix, Quimperlé, Finistère, Bretagne, France