John IV, Duke of Brittany

John IV
Drawing c.1700 of English-made effigy, on white arcaded chest tomb, Nantes Cathedral. Original monument destroyed. Drawing by Roger de Gaignières.[1]
Duke of Brittany
Reign	12 April 1365 – 1 November 1399
Predecessor	Joan, Duchess of Brittany, contested by John (IV)
Successor	John V
Count of Montfort (as John III)
Reign	16 September 1345 – 1 November 1399
Predecessor	John II
Successor	John IV
Earl of Richmond
Reign	20 June 1372 – 1 November 1399
Predecessor	John of Gaunt
Born	September–December 1339[2]
Died	1 November 1399 (aged 59–60) Nantes, Brittany
Burial	Nantes Cathedral[3]
Spouses	Mary of England ​ ​ (m. 1361; died 1361)​ Joan Holland ​ ​ (m. 1366; died 1384)​ Joan of Navarre ​ (m. 1386)​
Issue full list...	John V, Duke of Brittany Mary, Duchess of Alençon Margaret, Viscountess of Rohan Arthur III, Duke of Brittany Gilles, Lord of Ingrande Richard, Count of Étampes Blanche, Countess of Armagnac
Family	Montfort
Father	John of Montfort
Mother	Joanna of Flanders

John IV the Conqueror KG (in Breton Yann IV, in French Jean IV, and traditionally in English sources both John of Montfort and John V) (1339 – 1 November 1399), was Duke of Brittany and Count of Montfort from 1345 until his death and 7th Earl of Richmond from 1372 until his death.