How a decisive medieval battle ended in a surprising diplomatic victory for the loser
The Battle of Auray in 1364 was meant to settle the Breton War of Succession once and for all. Both sides fought with brutal intensity, refusing to take prisoners. Yet, despite a clear military triumph for the Anglo-Breton forces, the political outcome favored the French crown in an unexpected twist.
The conflict centered on the town of Auray, which had been held by Franco-Breton forces since 1342. By 1364, John de Montfort, supported by English commander John Chandos, besieged the castle. The defenders agreed to surrender if no relief arrived by Michaelmas, September 29. As the deadline approached, Charles of Blois and his French commander, Bertrand du Guesclin, arrived to challenge the siege. Montfort moved his troops to a superior position on the river's right bank, forcing his rivals to attack across marshy ground.
The engagement was exceptionally violent, as both armies had issued orders to show no mercy. While the Franco-Breton forces initially attacked, they lacked the tactical flexibility of their opponents. Montfort utilized a significant reserve force under Hugh Calveley to stabilize his lines, eventually counterattacking the enemy's wings. The Franco-Breton formation collapsed, Charles of Blois was killed, and the renowned du Guesclin was captured. The defeat was absolute, effectively concluding the long-standing war of succession.
The aftermath, however, defied the battlefield results. Under the 1365 Treaty of Guérande, the French king acknowledged John IV, son of Montfort, as the Duke of Brittany. Yet, in a move that stunned his English allies, the new Duke pledged his loyalty to Charles V of France instead of Edward III of England. What began as a crushing military defeat for the French monarchy transformed into a strategic success, as they secured the allegiance of the new Breton leader, leaving the English empty-handed despite their hard-won victory at Auray.
Source: Battle of Auray
