John de Montfort

Type Figure Region France Time c. 1295–1345 Also known as Montfort V

John de Montfort (c. 1295–1345), half-brother of Duke John III of Brittany, claimed the duchy in the 1341 Breton succession war, backed by Edward III…

Timeline

c. 1295–1340Montfort · BrittanyJohn was the half-brother of Duke John III of Brittany and long involved in duchy affairs. After the duke died without issue, he asserted a claim to the duchy based on male-line proximity, opposing Charles, who inherited through the Penthièvre line.
1341–1345Rennes · BrittanyAfter the succession crisis broke out in 1341, John quickly seized key strongholds of the duchy and gained Edward III's recognition. Imprisoned at Nantes, he escaped and continued organizing resistance. He fell ill during the siege of Rennes in 1345 and died that September; his widow Jeanne de Flanders and young son carried on the struggle.

Sources

John de Montfort | duke of Brittany https://www.britannica.com/biography/John-de-Montfort
War of the Breton Succession https://www.britannica.com/event/War-of-the-Breton-Succession