The Battle of Champtoceaux, often called the Battle of l'Humeau, is the opening action of the twenty-three-year-long War of the Breton Succession, a dynastic conflict in Brittany which becomes inevitably embroiled in the Hundred Years War between England and France.

This battle should have decided the war at a stroke, as John of Montfort, the leader of one faction, is made prisoner.

However his wife, Joanna of Flanders, and young son John escape imprisonment.

Their escape and continued support from his ally, England, allow continued resistance to flourish and eventually turn the tide.