ブルターニュ継承戦争
The War of the Breton Succession (, ) was a conflict between the Counts of Blois and the Montforts of Brittany for control of the Sovereign Duchy of Brittany, then a fief of the Kingdom of France. It was fought between 1341 and 12 April 1365. It is also known as the War of the Two Jeannes ("guerre des deux Jeannes") due to the involvement of two queens of that name (Jeanne (Joanna) of Flanders and Jeanne de Penthièvre).