The Battle of Champtoceaux, often called the Battle of l'Humeau, was the opening action of the 23-year-long Breton War of Succession, a dynastic conflict in Brittany which became inevitably embroiled in the Hundred Years War between England and France. The battle should have decided the war at a stroke, as the leader of one faction Jean de Montfort was made prisoner. His wife Joanna of Flanders and son young John escaped imprisonment. Their escape and continued support from his ally, England, allowed continued resistance to flourish and eventually turn the tide.