Jean de Beaumanoir

For the later marshall with the same name, see Jean de Beaumanoir (marquis).

Jean, or Jehan de Beaumanoir, marshal of Brittany for Charles of Blois, and captain of Josselin, is remembered for his share in the famous Combat of the Thirty during the War of Breton Succession (1341–1364) between the partisans of competing claimants for the Dukedom.

Robert Bemborough, the English captain of Ploërmel, who supported the rival claimant John de Montfort, was the nearest enemy leader. In 1351, Beaumanoir sent him a challenge, which resulted in an "emprise" — an arranged chivalric combat — which took place near Ploërmel, between picked combatants.

Beaumanoir commanded thirty Bretons, Bemborough a mixed force of twenty Englishmen (including Sir Robert Knolles and Sir Hugh Calveley), six German mercenaries and four Breton partisans of Montfort. The battle, fought with swords, daggers, spears, and axes, mounted or on foot, was extremely vicious. When de Beaumanoir was badly wounded and asked for water, his fellow combatant Geoffroy du Bois is supposed to have said to him "Drink your blood, Beaumanoir; your thirst will pass" (Bois ton sang, Beaumanoir, la soif te passera). De Beaumanoir's men emerged victorious, and he became an icon of medieval chivalry.

When his faction was eventually defeated at the Battle of Auray in 1364, de Beaumanoir helped to negotiate the Treaty of Guérande, which ended the war, receiving in return the title of Marshal of Brittany.

He married Marguerite de Rohan, daughter of Alain VII of Rohan and widow of Olivier de Clisson. Their daughter Jeanne was the wife of Charles de Dinan, Lord of Montafilant and Châteaubriant.