Siege of Hennebont

The siege of Hennebont took place between late May and late June 1342 when the forces of Charles of Blois conducted an unsuccessful siege of the fortified port of Hennebont, commanded by Joanna of Montfort. The conflict was a part of the Breton Civil War, a dynastic dispute between two claimants to the Duchy of Brittany which had broken out the previous year. A complicating factor was the pre-existing Hundred Years' War between France and England. Philip VI of France was supporting Charles of Blois, his nephew; Edward III of England had promised military assistance to Joanna, the wife of the rival claimant, John of Montfort. A truce between France and England was in place when the siege started but it expired in June.

Charles's French army overran eastern Brittany and captured John of Montfort. Joanna took up the cause and concentrated her resources in Hennebont. In late May 1342 Charles moved on the town. On arrival part of his army advanced against orders and attacked some of the town's defenders who were formed up outside its gate. More troops were pulled into this fight before the French were pushed back in a disorderly retreat. The Montfortists pursued, inflicting many casualties and burning the French camp. Two days later the French launched a series of better-planned assaults, but all were repulsed. The main French force moved on, leaving a detachment to attempt to starve the town into surrender. In late June, after a small English force had reinforced the town by sea, this too left. In July Charles was strongly reinforced and returned; the Montfortists abandoned Hennebont and redeployed further west, hoping for English reinforcements.