Person

John IV, Duke of Brittany

1339–1399 · 14th century · Also known as John of Montfort

John IV, Duke of Brittany, of the House of Montfort, won the War of the Breton Succession by defeating and killing his rival Charles of Blois at the Battle of Auray in 1364. Recognised as duke by the Treaty of Guérande in 1365, he balanced between England and France and established the Montfort dynasty, which ruled Brittany until 1488.

John IV, Duke of Brittany
Image: Rs-nourse · CC BY-SA 3.0 · Wikimedia Commons

Mentioned in 1 state history

Duchy of Brittany

See also

Cite this entry
APA
The Epoch Institute. (2026). John IV, Duke of Brittany. In The Epoch Institute Encyclopedia. https://the-epoch-institute.org/encyclopedia/john-iv-duke-of-brittany
MLA
“John IV, Duke of Brittany.” The Epoch Institute Encyclopedia, The Epoch Institute, 2026, https://the-epoch-institute.org/encyclopedia/john-iv-duke-of-brittany. Accessed .
Chicago
The Epoch Institute. “John IV, Duke of Brittany.” The Epoch Institute Encyclopedia. 2026. https://the-epoch-institute.org/encyclopedia/john-iv-duke-of-brittany.
Harvard
The Epoch Institute (2026) ‘John IV, Duke of Brittany’, The Epoch Institute Encyclopedia. Available at: https://the-epoch-institute.org/encyclopedia/john-iv-duke-of-brittany (Accessed: ).

Last reviewed October 2026Random entry ↻