Approximately 4,000–5,000 French, Breton and Genoese mercenaries (the largest field army ever assembled by Charles of Blois) laid siege to the town of La Roche-Derrien in the hope of luring Sir Thomas Dagworth, the commander of the only standing English field army in Brittany at the time, into an open pitched battle.

Charles, Duke of Brittany), in an effort to defeat the English longbowmen, gave orders to set up four encampments around the town's four gates.

However a sortie from the town, composed mainly of townsfolk armed with axes and farming implements, came from behind Charles's lines.

The battle features in Bernard Cornwell's historical novel Vagabond—part of his Grail Quest series of books, set against the background of the Hundred Years' War.

The Postgrad Chronicles, Death, Treachery, & A Victory Against the Odds: Sir Thomas Dagworth & The Battle of La Roche Derrien