John III, Duke of Brittany

John III
The funeral of John III
Duke of Brittany
Reign	27 August 1312 - 30 April 1341
Predecessor	Arthur II
Successor	disputed between: John IV and Joanna with Charles I
Spouse	Isabella of Valois Isabella of Castile Joan of Savoy
House	House of Dreux
Father	Arthur II
Mother	Marie, Viscountess of Limoges
Born	8 March 1286 Château de Champtoceaux
Died	30 April 1341(1341-04-30) (aged 55) Caen
Burial	Notre-Dame des Carmes
Religion	Roman Catholicism

John III the Good (in Breton Yann III, in French Jean III) (8 March 1286 – 30 April 1341) was duke of Brittany, from 1312 to his death. He was son of Duke Arthur II and Mary of Limoges, his first wife. John was strongly opposed his father's second marriage to Yolande of Dreux, Queen of Scotland after Mary's death, attempting to contest its legality.

In 1297, John was married to his first wife Isabelle of Valois, eldest daughter of Charles of Valois and his first wife Marguerite of Anjou and Maine. Her maternal grandparents were Charles II of Naples and Maria Arpad of Hungary. At the time of their marriage John was eleven years old and his bride only five.

Isabelle died childless in 1309. In 1310, John married his second wife Isabella of Castile, daughter of Sancho IV of Castile and his wife María de Molina. John was twenty-four years old and Isabella twenty-seven.

Isabella died childless in 1328. In 1329, John married his third wife Joan of Savoy, only child of Edward, Count of Savoy and Blanche of Burgundy. Her maternal grandparents were Robert II, Duke of Burgundy and Agnes of France, Duchess of Burgundy. John was forty-three years old and Joan about nineteen.

He predeceased his third wife by three years and remained childless. He was unwilling to cede the Duchy to his half-brother, John of Montfort, son of his hated step-mother. He wished to leave the Duchy to the French king, but his nobles objected. The marriage of his niece Joanna of Dreux to Charles of Blois gave Charles a plausible claim to the Duchy, but the matter was unresolved at John's death.

After his death John de Montfort claimed his rights as Duke, but French monarchy supported the Blois faction, triggering the Breton War of Succession (1341–1364), which opposed the House of Blois to the House of Montfort. This civil war became part of the Hundred Years' War, as England supported the Montfort faction against the French support for the House of Blois.

See also

• Dukes of Brittany family tree

John III, Duke of Brittany House of Dreux Cadet branch of the Capetian Dynasty Born: 8 March 1286 Died: 30 April 1341
Regnal titles
Preceded by Arthur II	Duke of Brittany 1312–1341	(disputed between: John IV and Joanna with Charles I)
	Viscount of Limoges 1301–1314	Succeeded by Guy VII
Preceded by Guy VII	Viscount of Limoges 1317–1331	Succeeded by Joan