The Duchy of Brittany was a medieval feudal state that existed between approximately 939 and 1547. Its territory covered the northwestern peninsula of Europe, bordered by the Atlantic Ocean to the west, and the English Channel to the north. It was also less definitively bordered by the river Loire to the south, and Normandy, and other French provinces, to the east. The Duchy was established after the expulsion of Viking armies from the region around 939. The Duchy, in the 10th and 11th centuries, was politically unstable, with the dukes holding only limited power outside their own personal lands. The Duchy had mixed relationships with the neighbouring Duchy of Normandy, sometimes allying itself with Normandy, and at other times, such as the Breton–Norman War, entering into open conflict.
Arthur II, of the House of Dreux, was Duke of Brittany from 1305 to his death. He was the first son of John II and Beatrice, daughter of Henry III of England and Eleanor of Provence.
John III the Good was Duke of Brittany, from 1312 to his death and 5th Earl of Richmond from 1334 to his death. He was the son of Arthur II, Duke of Brittany, and his first wife Marie, Viscountess of Limoges. John was strongly opposed to his father's second marriage to Yolande and attempted to contest its legality.
Joan of Penthièvre reigned as Duchess of Brittany together with her husband, Charles of Blois, between 1341 and 1364. Her ducal claims were contested by the House of Montfort, which prevailed only after an extensive civil war, the War of the Breton Succession. After the war, Joan remained titular Duchess of Brittany to her death. She was Countess of Penthièvre in her own right throughout her life.
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 due to the involvement of two rival duchesses of that name.
John of Montfort, sometimes known as John IV of Brittany, and 6th Earl of Richmond from 1341 to his death. He was the son of Arthur II, Duke of Brittany and his second wife, Yolande de Dreux. He contested the inheritance of the Duchy of Brittany by his niece, Joan of Penthièvre, which led to the War of the Breton Succession, which in turn evolved into being part of the Hundred Years' War between England and France. John's patron in his quest was King Edward III of England. He died in 1345, 19 years before the end of the war, and the victory of his son John IV over Joan of Penthièvre and her husband, Charles of Blois.
Charles of Blois-Châtillon, nicknamed "the Saint", was the legalist Duke of Brittany from 1341 until his death, via his marriage to Joan, Duchess of Brittany and Countess of Penthièvre, holding the title against the claims of John of Montfort. The cause of his possible canonization was the subject of a good deal of political maneuvering on the part of his cousin, Charles V of France, who endorsed it, and his rival, Montfort, who opposed it. The cause fell dormant after Pope Gregory XI left Avignon in 1376, but was revived in 1894. Charles of Blois was beatified in 1904.
John IV the Conqueror KG, was Duke of Brittany and Count of Montfort from 1345 until his death and 7th Earl of Richmond from 1372 until his death.
John V, sometimes numbered as VI, bynamed John the Wise, was Duke of Brittany and Count of Montfort from 1399 to his death. His rule coincided with the height of the Hundred Years' War between England and France. John's reversals in that conflict, as well as in other internal struggles in France, served to strengthen his duchy and to maintain its independence.
The now-extinct title of Earl of Richmond was created many times in the Peerage of England. The earldom of Richmond was initially held by various Breton nobles; sometimes the holder was the Breton duke himself, including one member of the cadet branch of the French Capetian dynasty. The historical ties between the Duchy of Brittany and this English earldom were maintained ceremonially by the Breton dukes even after England ceased to recognize the Breton dukes as earls of England and those dukes rendered homage to the King of France, rather than the English crown. It was then held either by members of the English royal families of Plantagenet and Tudor, or English nobles closely associated with the English crown. It was eventually merged into the English crown during the reign of Henry VII of England and has been recreated as a Dukedom.
Joanna of Flanders was Duchess of Brittany by her marriage to John of Montfort. Much of her life was taken up in defence of the rights of her husband and, later, son to the dukedom, which was challenged by the House of Blois during the War of the Breton Succession. Known for her fiery personality, Joanna led the Montfortist cause after her husband had been captured, and began the fight-back, showing considerable skill as a military leader.
Olivier V de Clisson, nicknamed "The Butcher", was a Breton soldier, the son of Olivier IV de Clisson. His father had been put to death by the French in 1343 on the suspicion of having willingly given up the city of Vannes to the English.
In the 11th and 12th centuries the Countship of Penthièvre in Brittany belonged to a branch of the sovereign House of Brittany. It initially belonged to the House of Rennes. Alan III, Duke of Brittany, gave it to his brother Eudes in 1035, and his descendants formed a cadet branch of the ducal house.
Louis II of Châtillon, son of Guy I, Count of Blois and Margaret of Valois, was count of Blois and lord of Avesnes from 1342 to 1346.
The House of Montfort-Brittany was a Breton-French noble family, which reigned in the Duchy of Brittany from 1365 to 1514. It was a cadet branch of the House of Dreux; it was thus ultimately part of the Capetian dynasty. It should not be confused with the older House of Montfort which ruled as Counts of Montfort-l'Amaury.
The Battle of Champtoceaux, often called the Battle of l'Humeau, was the opening action of the 23-year-long War of the Breton Succession, a dynastic conflict in the Sovereign Duchy of Brittany which became 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, was made prisoner. However his wife, Joanna of Flanders, and young son John escaped imprisonment. Their escape and continued support from his ally, England, allowed continued resistance to flourish and eventually turn the tide.
The first treaty of Guérande, signed on 12 April 1365, ended the Breton War of Succession.
Herve VII of Léon was a Breton lord, son of Herve VI, Lord of Léon and his wife Joanna of Montmorency. Also known as Herve. He succeeded his father as Lord of Léon in 1337. He was also Lord of Noyon-sur-Andelle. The Lords of Léon were a junior branch of the Viscounts of Léon which was founded by Harvey I, second son of Guihomar IV, Viscount of Léon. Herve VII won fame during the War of the Breton Succession.
John I, was Count of Penthièvre and Viscount of Limoges from 1364 to 1404, and the Penthièvre claimant to the Duchy of Brittany.
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