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. | |
| 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 | |
| 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 |
| Died | 1 November 1399 (aged 59–60) Nantes, Brittany |
| Burial | |
| Spouses | |
| Issue full list... |
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| 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.